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Lukas666

Anyone else have this annoying issue?

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So I finished a Hornet Re release build on the weekend and been running it around in the basement that’s all open cause it’s like -100 degrees in Canada right now. Really happy with this buggy but there was one thing that annoyed the badword out of me. I found myself adjusting the steering trim constantly, like it was bad!.... adjust it to go straight then burn around a bit and blam it’s driving crooked as badword again. Checked the servo and screw holding on servo horn and saver again tightened it a bit and still did it. Then adjusted the EPA steering on the Futaba remote as I thought it was maxing out the steering and trying to pull it further than it can, that seemed to help a bit. I think however the issue is when I bump into things on the front end in the house it messes up the trim and I constantly have to re adjust. The bumper isn’t that big so if you hit things it hits a wheel a lot. The servo isn’t the best but it’s definitely not the cheapest, it’s a Savox blue waterproof metal gear.... not a bad servo I have one in my lunchie and it’s been great. Also about 5 hrs after I painted the wing I seen this? Whats that all about ? What is that? It looks fine underneath so it is on the first coat. Not a big deal as this is a runner not a shelf piece but still annoying.

D9393C66-4926-44E6-BF44-7C92F40E72B2.jpeg

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The steering is always my biggest headache. I find im always adjusting. However, I did learn about the endpoint adj and that seemed to help the overall issue. But i do feel your frustration as far as alligning the steering to be true all the time.

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5 minutes ago, Finnsllc said:

The steering is always my biggest headache. I find im always adjusting. However, I did learn about the endpoint adj and that seemed to help the overall issue. But i do feel your frustration as far as alligning the steering to be true all the time.

Is it a common issue you think with buggies such as the hornet and grasshopper and frog with a small bumper and little front tires?

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i think 2wd buggies are the worst if you run on asphalt. Offroad its not as much of an issue.

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I can't say I've ever suffered this with my buggies but then I don't own a grasshopper or hornet? I can honestly say this has never been an issue with my Thundershots, Avante2001, Egress, Vanquish or even the new buggies such as Cougar, DT02 and DT03. We've crashed loads of times into kerbs, fences and plant pots. So I'm guessing it is just an issue with this chassis? We don't even use high torque servos, all our buggies use Futaba S3001 or Futaba archaic FP S148 servos and alot of our crashes are offset front collisions so bumper doesn't protect the front wheels.

 

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I only ever had the issue of non centering steering on my b5m race car, and it turned out to be a tight shock lower ball cup, after a jump it would hold it on one side lower than the other. Now I always check all suspension is free to move especially when the shocks are removed.

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What about that bubble or whatever the heck it is on the fin? Left side by the “T”... maybe I put the fin on to early? Right side is good that’s just a glare there. 

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Has the paint separated from the plastic but not actually cracked? Ive had that on a couple of XB pre painted shells.

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Ya looks like it kinda... like a bubble. Hopefully doesn’t get worse like a crack in a windshield. I did wash it before hand.

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It doesn’t look like the paint has adhered there 

was the shell fully dry?

water “pooling” is always an issue

you could use some paint remover in that area and then respray that area 

JJ

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1 hour ago, Problemchild said:

It doesn’t look like the paint has adhered there 

was the shell fully dry?

water “pooling” is always an issue

you could use some paint remover in that area and then respray that area 

JJ

Pretty sure it was dry but who knows.... ya I thought of touching it up I’m sure it’ll get bashed up this summer anyway. I thought these Lexan bodies were supposed to be tough as nails too?... just ran into my daughters play kitchen in the basement and put a small crack in the lexan  above the front wheel, where you cut out for the shock. I’ll probably run them a couple years till I get sick of them, buy new bodies for the Lunchbox and Hornet, repaint and shelf them. Maybe pull them out here and there. Buy something tough and really fast to run like a Mad van or something less iconic.

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Had the steering issue a few times on the hornet. Check the clearance of the servo saver against the chassis.. Its quite close and can cause it to snag giving the issue you have.. Depending on the servo I've assisted the clearance before with a file.. 

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From memory the steering arms are pretty light on the Hornet. The steering rod(s) might be getting pulled out of the ball end thread by thread if it is taking any small to medium hits on the front wheels.

Worth checking the length of them to see, or seeing if they are bent. My  Super Hornet suffered from it a lot. Options are to  stop hitting stuff, or put beefier steering rods in.

image.png.c2478bb1612ff22892caba9de2d93e0d.png

 

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6 hours ago, zakspeed said:

Had the steering issue a few times on the hornet. Check the clearance of the servo saver against the chassis.. Its quite close and can cause it to snag giving the issue you have.. Depending on the servo I've assisted the clearance before with a file.. 

Very good point and I did notice that during the build, I’m pretty sure there is clearance but will check again thanks.

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4 hours ago, LeftyAl said:

From memory the steering arms are pretty light on the Hornet. The steering rod(s) might be getting pulled out of the ball end thread by thread if it is taking any small to medium hits on the front wheels.

Worth checking the length of them to see, or seeing if they are bent. My  Super Hornet suffered from it a lot. Options are to  stop hitting stuff, or put beefier steering rods in.

image.png.c2478bb1612ff22892caba9de2d93e0d.png

 

I’ve looked many times they’re not bent, it’s more like bumping into things really not hitting them full tilt lol.... those are rough measurements cause I remember setting them to that about a week and a half a go and then when the wheels were all mounted I had to crank them right in till there was basically no threads left to get the toe correct. If what your describing is happening the toe would be way out which it is not but I will re check for sure thanks.

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OK - there's a few things to check here.  As has been mentioned, the steering links on the original were very thin, not sure if they're the same on the re-re.  You say they're not bent, so hopefully that's not the issue.

Another point - you're using a Savox servo, does it have a metal splined drive, or a plastic one?  In my experience, Tamiya servo savers work well enough on plastic splines where the self-tapping screw is held in place, but they don't work so well on metal splines because you need to torque up the screw in order to stop it falling out.  This torque clamps both halves of the servo saver together and stops it from re-centring after it's taken a knock.  I had this loads of times in my early race days when I switched away from cheap Acoms servos to better metal geared ones.  The best solution I've found is to add a bit of threadlock to the machine screw, then make sure it's loose enough that the servo saver can return to centre after being shunted.

Adjusting the endpoint can feel like it helps with this because if you have too much throw, once you reach 100% on your hubs (but, say, 90% on your servo throw) you will be taking up that last 10% in the servo saver.  If the servo saver is too tight, it won't re-centre when you return to the middle and the trim will be off.  Now you steer fully the other way and the opposite happens, it over-adjusts in the opposite direction, so you're constantly adjusting the trim one way then the other.

Also as mentioned above, check the servo saver or linkages aren't binding on anything and make sure all the steering moves smoothly.

Finally you could adjust the steering rods to give a tiny bit of toe out, that might help take up any slack in the front end - the scrubbing effect of the wheels might pull out any slop to give more precise steering.  Don't overdo it as it will mess with the handling.

As for the wing - the five hours between painting and noticing the bubble, was the wing sitting and drying or were you racing around the basement?  I'd normally allow at least a day after painting for the paint to cure (I wouldn't be surprised if it's still chemically curing after several days, even more in cooler ambient temps) before I started bashing around.  Even screwing a wing onto a body will put some twist through the plastic which might be enough to flake the paint off.  As said above it could be you had a water bubble in that area when you started painting - it's easy to miss a little bubble that forms in a place like that - or it could be that the paint pooled a little too thick in that area which reduces how much it can flex.

Did you wash the body with detergent before you painted?  If there was any release residue on the body it will affect how well the paint adheres.

As for the cracked body - how warm is it?  It's a sad fact of the RC hobby that plastics get more brittle as they get cold, I was hoping to have some monster truck fun in my garden this weekend but temps were down around 0-1 degrees C all day, that's probably quite balmy compared to your part of the world right now but still cold enough for plastic to crack instead of flex, so I left the trucks on the shelf and lit the log fire instead.  Also how neat was your cut around that area?  If memory serves it's a bit of a fiddly area, if there was a rough edge or spiky bit it could have acted as a stress point in what is already a narrow area.  Lexan is tougher than ABS for basher bodies but unfortunately it has its limits, and my experience of catching my toe on play kitchens is they're a lot harder and heavier than they look.  You might not have had that kind of impact if you were running outside.

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3 hours ago, Mad Ax said:

OK - there's a few things to check here.  As has been mentioned, the steering links on the original were very thin, not sure if they're the same on the re-re.  You say they're not bent, so hopefully that's not the issue.

Another point - you're using a Savox servo, does it have a metal splined drive, or a plastic one?  In my experience, Tamiya servo savers work well enough on plastic splines where the self-tapping screw is held in place, but they don't work so well on metal splines because you need to torque up the screw in order to stop it falling out.  This torque clamps both halves of the servo saver together and stops it from re-centring after it's taken a knock.  I had this loads of times in my early race days when I switched away from cheap Acoms servos to better metal geared ones.  The best solution I've found is to add a bit of threadlock to the machine screw, then make sure it's loose enough that the servo saver can return to centre after being shunted.

Adjusting the endpoint can feel like it helps with this because if you have too much throw, once you reach 100% on your hubs (but, say, 90% on your servo throw) you will be taking up that last 10% in the servo saver.  If the servo saver is too tight, it won't re-centre when you return to the middle and the trim will be off.  Now you steer fully the other way and the opposite happens, it over-adjusts in the opposite direction, so you're constantly adjusting the trim one way then the other.

Also as mentioned above, check the servo saver or linkages aren't binding on anything and make sure all the steering moves smoothly.

Finally you could adjust the steering rods to give a tiny bit of toe out, that might help take up any slack in the front end - the scrubbing effect of the wheels might pull out any slop to give more precise steering.  Don't overdo it as it will mess with the handling.

As for the wing - the five hours between painting and noticing the bubble, was the wing sitting and drying or were you racing around the basement?  I'd normally allow at least a day after painting for the paint to cure (I wouldn't be surprised if it's still chemically curing after several days, even more in cooler ambient temps) before I started bashing around.  Even screwing a wing onto a body will put some twist through the plastic which might be enough to flake the paint off.  As said above it could be you had a water bubble in that area when you started painting - it's easy to miss a little bubble that forms in a place like that - or it could be that the paint pooled a little too thick in that area which reduces how much it can flex.

Did you wash the body with detergent before you painted?  If there was any release residue on the body it will affect how well the paint adheres.

As for the cracked body - how warm is it?  It's a sad fact of the RC hobby that plastics get more brittle as they get cold, I was hoping to have some monster truck fun in my garden this weekend but temps were down around 0-1 degrees C all day, that's probably quite balmy compared to your part of the world right now but still cold enough for plastic to crack instead of flex, so I left the trucks on the shelf and lit the log fire instead.  Also how neat was your cut around that area?  If memory serves it's a bit of a fiddly area, if there was a rough edge or spiky bit it could have acted as a stress point in what is already a narrow area.  Lexan is tougher than ABS for basher bodies but unfortunately it has its limits, and my experience of catching my toe on play kitchens is they're a lot harder and heavier than they look.  You might not have had that kind of impact if you were running outside.

Yes the spline drive is metal on the Savox and that does make sense. When I did an initial check to see if it was loose I did get some more tightening out of it but yeah the servo saver might not be operating as it should now with it sinched up right tight. Can any of the servo drive attachments that come with the servo be used instead? I was contemplating that as well. I can try loosening it and putting some thread locker on it. What led me to think it needed to be tightened tho was upon inspection and manually grabbing the front wheels and trying to make them turn there was some slip there like it would skip some splines before I’d get it to move?.... hence I thought it needed to be tightened and after I did it doesn’t do that anymore by hand it grabs the splines and turns? I haven’t  seen an original Hornet but yes I’m guessing the steering linkage is the same cause these ones are pretty light. Bear in mind this is a brand new unit with maybe 2 hrs of run time testing it out here and there in the house, I haven’t taken it off jumps or really thrashed on it yet cause it’s winter and too cold to try it outside. Everything is trued up and straight as an arrow I can post pics later when I get home so I’m pretty positive it’s not a case of anything bent or stripped or binding or any of that. It’s gotta be that servo saver issue your speaking of. But even that maybe doesn’t make sense as it drives straight after adjusting till maybe you bump your something at 1/2 throttle then it drives crooked again and needs the trim adjusted? Weird.... isn’t that the purpose of the saver for instances like that? The body was washed with diluted dish soap and rinsed with water but yeah I’m guessing there was maybe some moisture there or I put the wing on too soon. The crack by the wheel well was done in the house at 22degrees Celsius so cold wasn’t a factor but yeah probably just a weak stress point no big deal it probably won’t be the last lol.

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I have found that the metal splined servos tend to need a fine thread screw. Are you using the screw that came with the Savox or the course thread one from the Hornet kit.

When diagnosing issues like this I would take the servo saver apart, feel for any burred edges (smooth out of need be) and reassemble. When tightening the screw you should get no back and forward movement from the servo saver (it should be a good tight fit).

image.png.07b29cddc46793f6ff3d408b9899cc3b.png

Sometimes the screw can be too long or too short. If too long you can put a extra spacer in with P1.

Does P5 or P6 fit your Savox servo?

It could be the servo, I've had brand new servos misbehave and I found out the hard way that ebay had plenty of fake Futaba S3003 servos. Do you have another servo to check against? 

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6 minutes ago, LeftyAl said:

I have found that the metal splined servos tend to need a fine thread screw. Are you using the screw that came with the Savox or the course thread one from the Hornet kit.

When diagnosing issues like this I would take the servo saver apart, feel for any burred edges (smooth out of need be) and reassemble. When tightening the screw you should get no back and forward movement from the servo saver (it should be a good tight fit).

image.png.07b29cddc46793f6ff3d408b9899cc3b.png

Sometimes the screw can be too long or too short. If too long you can put a extra spacer in with P1.

Does P5 or P6 fit your Savox servo?

It could be the servo, I've had brand new servos misbehave and I found out the hard way that ebay had plenty of fake Futaba S3003 servos. Do you have another servo to check against? 

No extra servo to try no.... mine looks exactly like that pic I put on all the same parts via the Tamiya instructions except I did not use the screw out of the Tamiya kit I used a fine thread screw that came with the Savox servo. You can’t even use the screw they tell you in the Tamiya instructions with these servos it’s completely a different thread pitch and I’d like to think most guys would notice that. The screw tightens right up it’s not too long. It’s gotta be the servo itself or just a nature of the beast... I’ll mess around with it some more maybe tonight. I’ll post pics shortly.

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OK - few interesting points to go on here :)

Quote

Can any of the servo drive attachments that come with the servo be used instead?

Yes, provided the number of splines match.  You can swap out the servo saver for a solid servo horn to see if this solves your problem, but be advised any knocks will be transferred into the steering assembly and the servo.  The weakest point is probably the steering links, so they will bend.  Savox servos are among the best and even the budget ones are fairly tough, but it's worth knowing the risks.  You can buy replacement gears for the Savox if you break them.  You can also use a servo horn from your Savox servo box (you might need to trim off extra horns if it's a bar or star shape and modify the linkages).

Quote

What led me to think it needed to be tightened tho was upon inspection and manually grabbing the front wheels and trying to make them turn there was some slip there like it would skip some splines before I’d get it to move?....

That shouldn't happen - either the servo should turn when a force is applied (assuming the radio is powered off) or the plastic spring around servo saver should open up and allow the servo saver to move.  It shouldn't be skipping splines.  Check that you have the right adapter installed (P5 or P6 in the manual page posted above).  They are designed for different servo brands.  IIRC one is marked ACOMS/SANWA and has 23 splines, one it marked TAMIYA/FUTABA and has 25 splines.  I'm pretty sure you need the 25 spline adapter for the Savox servo but try both and see what fits best.  This may be the root of your problem - if the splines are jumping that easily it will keep going out of trim.

Quote

It’s gotta be that servo saver issue your speaking of. But even that maybe doesn’t make sense as it drives straight after adjusting till maybe you bump your something at 1/2 throttle then it drives crooked again and needs the trim adjusted? Weird.... isn’t that the purpose of the saver for instances like that?

That is the purpose - provided it's working properly and not sticking.  When you set it up, the plastic spring (shaped like a letter C) around the servo saver will be closed and the servo saver will be central.  When you drive off and knock something, or you turn the servo beyond what the hubs allow, the spring opens up - this allows the servo saver to move, effectively "saving" the servo from impacts.  Now in theory, as soon as you drive past the impact, or release the steering, the spring should close again and the servo saver will return to its normal position and steering will be straight again - however, if the servo saver is binding, it won't return to its normal position, it will stay where it is.  When you return your steering channel to the centre position, the servo saver will still be on an angle and so your steering won't be straight.

So to reiterate - the servo saver should be able to protect your servo AND provide straight driving without having to constantly re-trim.  If it's too tight, it may not return to its normal position and provide straight steering, or it may not protect your servo.

I hope that helps :) 

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5 hours ago, Mad Ax said:

OK - few interesting points to go on here :)

Yes, provided the number of splines match.  You can swap out the servo saver for a solid servo horn to see if this solves your problem, but be advised any knocks will be transferred into the steering assembly and the servo.  The weakest point is probably the steering links, so they will bend.  Savox servos are among the best and even the budget ones are fairly tough, but it's worth knowing the risks.  You can buy replacement gears for the Savox if you break them.  You can also use a servo horn from your Savox servo box (you might need to trim off extra horns if it's a bar or star shape and modify the linkages).

That shouldn't happen - either the servo should turn when a force is applied (assuming the radio is powered off) or the plastic spring around servo saver should open up and allow the servo saver to move.  It shouldn't be skipping splines.  Check that you have the right adapter installed (P5 or P6 in the manual page posted above).  They are designed for different servo brands.  IIRC one is marked ACOMS/SANWA and has 23 splines, one it marked TAMIYA/FUTABA and has 25 splines.  I'm pretty sure you need the 25 spline adapter for the Savox servo but try both and see what fits best.  This may be the root of your problem - if the splines are jumping that easily it will keep going out of trim.

That is the purpose - provided it's working properly and not sticking.  When you set it up, the plastic spring (shaped like a letter C) around the servo saver will be closed and the servo saver will be central.  When you drive off and knock something, or you turn the servo beyond what the hubs allow, the spring opens up - this allows the servo saver to move, effectively "saving" the servo from impacts.  Now in theory, as soon as you drive past the impact, or release the steering, the spring should close again and the servo saver will return to its normal position and steering will be straight again - however, if the servo saver is binding, it won't return to its normal position, it will stay where it is.  When you return your steering channel to the centre position, the servo saver will still be on an angle and so your steering won't be straight.

So to reiterate - the servo saver should be able to protect your servo AND provide straight driving without having to constantly re-trim.  If it's too tight, it may not return to its normal position and provide straight steering, or it may not protect your servo.

I hope that helps :) 

Seems it’s sticking a bit but not every time, opens up when I turn the front wheels by hand but then doesn’t close about 1/4 times. Maybe I should loosen screw slightly and put some Tamiya grease between the pieces? The spline drive I used was the only one that fit there was no question about that I checked it like 3 times... wasn’t like 2 were close, only 1 fit. 

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5 hours ago, Mad Ax said:

OK - few interesting points to go on here :)

Yes, provided the number of splines match.  You can swap out the servo saver for a solid servo horn to see if this solves your problem, but be advised any knocks will be transferred into the steering assembly and the servo.  The weakest point is probably the steering links, so they will bend.  Savox servos are among the best and even the budget ones are fairly tough, but it's worth knowing the risks.  You can buy replacement gears for the Savox if you break them.  You can also use a servo horn from your Savox servo box (you might need to trim off extra horns if it's a bar or star shape and modify the linkages).

That shouldn't happen - either the servo should turn when a force is applied (assuming the radio is powered off) or the plastic spring around servo saver should open up and allow the servo saver to move.  It shouldn't be skipping splines.  Check that you have the right adapter installed (P5 or P6 in the manual page posted above).  They are designed for different servo brands.  IIRC one is marked ACOMS/SANWA and has 23 splines, one it marked TAMIYA/FUTABA and has 25 splines.  I'm pretty sure you need the 25 spline adapter for the Savox servo but try both and see what fits best.  This may be the root of your problem - if the splines are jumping that easily it will keep going out of trim.

That is the purpose - provided it's working properly and not sticking.  When you set it up, the plastic spring (shaped like a letter C) around the servo saver will be closed and the servo saver will be central.  When you drive off and knock something, or you turn the servo beyond what the hubs allow, the spring opens up - this allows the servo saver to move, effectively "saving" the servo from impacts.  Now in theory, as soon as you drive past the impact, or release the steering, the spring should close again and the servo saver will return to its normal position and steering will be straight again - however, if the servo saver is binding, it won't return to its normal position, it will stay where it is.  When you return your steering channel to the centre position, the servo saver will still be on an angle and so your steering won't be straight.

So to reiterate - the servo saver should be able to protect your servo AND provide straight driving without having to constantly re-trim.  If it's too tight, it may not return to its normal position and provide straight steering, or it may not protect your servo.

I hope that helps :) 

 

9FB70BEC-159E-4D2F-B0BD-DE2448CBE6B3.jpeg

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On 2/11/2021 at 12:14 AM, zakspeed said:

Had the steering issue a few times on the hornet. Check the clearance of the servo saver against the chassis.. Its quite close and can cause it to snag giving the issue you have.. Depending on the servo I've assisted the clearance before with a file.. 

There’s clearance

B5A3DB2C-F48D-4128-B1D3-742127C6A0EE.jpeg

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I noticed while assembling and centering the servo that the spine drive was always off to one side in the centered position. Pull it off and try to correct it and it’s off to the opposite side. Weird. 

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