Spektrum TX Teflon Smooth Throttle Mod

[jimmy77611]

Tired of greasing and re-greasing that sticky spektrum throttle? A guy that I've flown with (and is a member here) showed me this ultimate mod to smooth out my throttle stick, and say goodbye to grease.

This mod for sure works on DX6i, DX7s, DX8, DX9, and maybe others. Maybe any TX with a metal friction strap?

You'll need some teflon cloth or sheeting, basically it's a really thin sheet of teflon. It can be found on ebay, but I got mine from my buddy at the field. You'll also need a heat gun and heat shrink.

1. Take the TX back off and remove the metal friction strip on the throttle stick. Clean off any grease from the gimbal and strip.

2. Cut a strip of teflon cloth the same width as the smooth side of the strip. I've actually found that putting 3 layers helps to get the right tension for me, but feel free to experiment here.

3. Cut two small pieces of heat shrink tube to attach the strips of teflon to the strap. See pics. Just make sure it's not long enough to hit the plastic on the gimbal.

4. Put the strap back on and adjust tension to your liking.

Simple as that! I found that with only one layer of teflon, the throttle was too smooth, even tightened all the way down. Three layers did the trick for me.

Smoooooooth!


Update: Check post #135 before you buy anything

[TheBum]

I'll bet it's the same fellow who showed it to me at the Aero Hobbies Fun Fly. I'm bad with names, so I don't remember his. Thanks for posting.

As it turns out, I run the throttle stick on my DX9 loose enough that I don't need it.

[keithhoak]

That guy would be me. I like my collective pretty stiff. I tried lots of suggestions but this was the only fix that worked for me.

I read about this kind of mod about 3 years ago on one of the forums but I could never find it again.

Good description of the mod Jimmy.

[TheBum]

Originally Posted by keithhoak

That guy would be me. I like my collective pretty stiff. I tried lots of suggestions but this was the only fix that worked for me.

I read about this kind of mod about 3 years ago on one of the forums but I could never find it again.

Good description of the mod Jimmy.

+1.

Just so you and others won't have as much trouble finding it next time, I'm going to make this a sticky. I've seen firsthand how smooth this mod makes the throttle stick. I'll probably do the mod on my dedicated simulator TX (DX7).

Unfortunately, I misplaced the piece of cloth you gave me, so I guess I'll have to buy a sheet (at which time the piece you gave me will show up).

[Xrayted]

What is teflon sheeting typically used for? I looked it up and can find many sources to order online, but its always listed as some sort of heat resistant art transfer material, so is this something I can find locally at a craft store? I don't want to pay $6 shipping for a $2.50 sheet of material if I can get it locally.

EDIT: Looks like it can be found in many craft and art stores, and also used in T Shirt printing industry. Shouldnt be hard to source locally

[TheBum]

I think Keith said he bought his at a chain craft store (Michael's? Again with that horrible memory!)

It seems that the optimum Google search term is "teflon pressing sheet".

[keithhoak]

I got mine at Joann Fabrics but it is a good sized sheet, 18" x 18" for about $10.

Just looked and it is on sale for $6.50.

Walmart list them on their website also.

[TheBum]

Is it this one?

http://www.joann.com/june-tailor-non...n/3754793.html

I know that's Teflon because the image on the June Tailor website actually says "Teflon" and the UPCs are identical. The Joann website says "Online Only" though, as does the Wal-Mart web site. How long ago did you buy yours?

I think the piece you gave me is somewhere in my tool tote. I'll do another search this evening.

[Xrayted]

I also just remembered that you can get Teflon tape by the roll in the plumbing dept at any home or hardware store. It's used to prevent leaks on threaded plumbing fittings, and is very thin and slickery feeling. My. Father used to always have a roll in his tool box. Dirt cheap too. http://www.homedepot.com/p/Unbranded...8502/202280370

[TheBum]

It's rather flimsy and probably wouldn't last long. The sheeting we're talking about has fiberglass as a substrate, I believe.

[Xrayted]

Originally Posted by TheBum

It's rather flimsy. The sheeting we're talking about has fiberglass as a substrate.

Yes, it's very thin, but very hard to break. You would have to wrap a few layers around the tension spring, but I think it would work, and is super slick, so it won't wear through very easily, especially with a few layers and the fact that there is very little pressure on it. I might give it a shot just as a test and report back.

[CZorzella]

Originally Posted by jimmy77611

Simple as that! I found that with only one layer of teflon, the throttle was too smooth, even tightened all the way down. Three layers did the trick for me.

How thick is the teflon sheet that you are using?

[keithhoak]

CZorzella, the pressing sheet material I am using is about 0.0035" thick. It has a substrate which makes it very tough. I used one piece on my DX7 for 2 years with little wear.

TheBum, Yes that is the one. I was in the store in Plano last month with my wife and they had a package on the rack, but they may have quit carrying it in the store on a regular basis.
I bought mine about 3 years ago.

[bovi_7]

THX

[jolynsbass]

Originally Posted by Xrayted

Yes, it's very thin, but very hard to break. You would have to wrap a few layers around the tension spring, but I think it would work, and is super slick, so it won't wear through very easily, especially with a few layers and the fact that there is very little pressure on it. I might give it a shot just as a test and report back.

I just tried this with Teflon tape (plumber's tape) tonight on my new (used) DX8, which had a "sticky" throttle - once it was moving, it was fine, but if it was stopped, it would "lunge" in the direction of your movement, as it overcame friction.

Anyway, works like a charm. I should've taken pics or something, but here's what I did with the tape:
1) Cut a 5-6 inch piece of Teflon tape
2) fold it lengthwise once
3) fold it widthwise at least twice, perhaps it was even three times... At any rate, it ended up approximately the same width as the tension bar, and was several layers thick, and all one piece.
4) then I heat-shrinked the ends onto the bar, and put it back.

The hardest part about this mod was just getting those rubber strips off the sides of the radio.

Now my throttle is smooth as butter. Just enough tension on the stick so it doesn't respond to random bits of thumb movement (shaking as you move rudder), but it moves smoothly and precisely to the next position when you move it up or down.

Thanks so much for this thread!

[Xrayted]

Originally Posted by jolynsbass

I just tried this with Teflon tape (plumber's tape) tonight on my new (used) DX8, which had a "sticky" throttle - once it was moving, it was fine, but if it was stopped, it would "lunge" in the direction of your movement, as it overcame friction.

Anyway, works like a charm. I should've taken pics or something, but here's what I did with the tape:
1) Cut a 5-6 inch piece of Teflon tape
2) fold it lengthwise once
3) fold it widthwise at least twice, perhaps it was even three times... At any rate, it ended up approximately the same width as the tension bar, and was several layers thick, and all one piece.
4) then I heat-shrinked the ends onto the bar, and put it back.

The hardest part about this mod was just getting those rubber strips off the sides of the radio.

Now my throttle is smooth as butter. Just enough tension on the stick so it doesn't respond to random bits of thumb movement (shaking as you move rudder), but it moves smoothly and precisely to the next position when you move it up or down.

Thanks so much for this thread!

Good to know the plumbers stuff works! I never got around to trying it although I have some in the tool box. Sounds like a good rainy day project. I have a DX9, so no more rubber grip removal to get inside anymore

[CyprusFlyer]

Interesting, had a thought, Synergy helicopters use some teflon heatshrink tube for use on the CF tail control rod. It is used in two places where the control rod runs through the guides off the tail boom, might just work,

[KSHeli]

I just found this
http://www.buyheatshrink.com/heatshr...ing/teflon.htm
Found some other sites but they sold in 100 ft rolls, , no help.

The above site will sell in 4 foot lengths for about $4, I didn't check the S&H.
Features of PTFE Heat shrink:

Continuous operating temperature -454°F to 500°F (-270°C to 260°C)
Outstanding resistance to almost any chemical known (exceptions: alkali metals in molten state, fluorine gas at high temperatures, chlorine trifluoride).
FDA and USP Class VI approved
Very low coefficient of friction
Good dielectric strength
Flame rating UL94 V0 and VW-1
Limiting Oxygen Index greater than 95
ETO and autoclave sterilizable
Mil spec approved (AMS-DTL-23052/12)
A few notes on shrinking PTFE:
1) Always assure good ventilation in the immediate work area prior to beginning the heat shrink process. Fumes may cause nausea and dizziness.
2) It is imperative that the tubing be heated uniformly until it becomes clear (gel state). This transition from crystalline to amorphous must take place, since shrinkage will only occur during recovery from the gel state (re-crystallizing).
3) When using a mandrel to shrink the tubing, it is important to pre-heat the mandrel to assure even and uniform shrinkage.
4) If the tubing begins to crack, chances are you overheated the material.
5) Also, higher shrink ratios will require higher shrink temperatures.

[TheMark]

Just finished up this mod to my DX9.

I tried just replacing the grease with TriFlow synthetic grease = no difference
I tried sanding the plastic cam with 600 grit sand paper = better, but enough
I tried polishing the inside of the metal finger to a mirror finish = better yet, not enough...

Finally, I tried this mod. MUCH improved and no difference in tension from top to bottom.

Thanks to all who figured this out!

[EEngineer]

What if one....removes the gymbal strap and, using a mallet, removes
the strap "dimple"?

And then, one can adjust the the straps to suit you.

The strap "dimple" is the cause of the "ratcheting effect"....

Some TX manufacturers have an aftermarket "dimple-less" strap.

FWIW