Jetdesign

My Feedback: (8)

Please don't ask me how this one got stuck in my brain last night...

For old times' sake:
http://www.youtube.com/watch?v=QHboMLW-Zn0

Jetdesign

My Feedback: (8)

So I got a 3517 servo with all plastic gears. I also got a 3517 servo with metal gears. I think the all plastic gear servo is older, but new. This is for dual elevator servos in my new baby.

Is there any risk if I regear them with the same gear set, or should I replace the older servo ? I don't want some slight elevator offset to make my plane fly crooked, LOL

Ryan Smith

My Feedback: (25)

Joe,

Did you buy them new or used? Sounds like one has simply been re-geared; to the best of my recollection, the 3517 has always been a metal gear servo.

Jetdesign

My Feedback: (8)

They are both NIP; I think the 3517 started out with nylon gears and over time it got a metal output gear, and finally metal gears. The package is almost identical except for the mg part, and the specs are the same. Should be OK I guess? Not really sure what would happen over time to any components, so hopefully response/speed/etc would be the same.
http://www.servodatabase.com/servo/jr/ds3517

PatternFlyer

My Feedback: (182)

JR DS3517 actually came out with plastic gear version as Joe mentioned above.

Later, Metal gear versions came out, but DS3517 standard got discontinued.

Reason was the heli guys kept on breaking the gears on 3517.

I have a few of those at home too. Was going to use them on Kyosho Flip, but decided to go with metal gears instead. For use on elevators of Pattern plane should be good.

Jetdesign

My Feedback: (8)

what is the right thickness of carbon plate for making motor mounts? This would be bolted or glued to a nose ring and supported in the rear. Is 1/16" too thin?

woodie

While carbon plate is very strong, it isn't the lightest composite around, nor the easiest to cut. I prefer 1/8" end grain balsa/carbon laminate (carbon on both sides. Very strong, fairly easy to cut. If you are using the rear support for the Advance, 1/8" end grain/carbon laminate is plenty strong enough. On my Spark (small diameter nose ring), I only use the 1/8" end grain/carbon laminate with no rear support. No issues so far......

Woodie

tewalker01

My Feedback: (5)

Don,

Interesting, I thought that it was standard practice for front mount inrunners to also have a rear support. I know that the Spark hasthe total nose of the plane reinforced withcarbon fiber cloth. Is this the reasonyou can use justa front mount of1/8" balsa/carbon laminate?

Terry

woodie

Terry, yes it is common practice to use a rear support for in-runners, however, the Advance (yes, an in-runner) is configured more like an outrunner with a a large base/mounting plate area that goes against the nose ring plate. It is also a small nose ring, the Advance barely fits into the nose so there is not much unsupported area outside the motor mounting plate. The entire nose of the Spark is carbon fibre too.

After I installed the motor, I gave it the ole 'grab a prop blade and pull hard/twist' test (highly calibrated BTW) and nothing moved so I did not install the rear support.

I believe the new Angel Shadow is also set up this way.

Like I said, so far no problems.....

Woodie

Jetdesign

My Feedback: (8)

I tried the laminated end-grain balsa, had issues with the balsa crushing. I chose carbon to avoid that, to allow for a mount that will be very robust to installing/removing the motor, etc. Even the glassed-ply motor box in my Sebart Wind 110 started to crush a little after many flights and showed signs of fatigue.

I just bought some 1.5mm and 2mm carbon and have some 2.5mm carbon here. It seems to me that the 'commercially available' G10 and carbon mounts are somewhere between 1.5 and 2mm. It would be nice to get away with the 1.5mm. The Advance will be front- and rear supported.

http://www.znline.com/photos.php?sou...372463&index=0
javascriptopupWindow('http://www.f3aunlimited.com/webstore/index.php?main_page=popup_image&pID=193')

Jetdesign

My Feedback: (8)

For pull-pull, I am considering the following cable options - would like to hear your thoughts
1) 7-strand stainless fishing leader, 40lb test, nylon coated
http://www.afwhiseas.com/product-p/c045b-0.htm

2) 49-strand stainless 'knotable' fishing leader, 40lb test, nylon coated (super flexible and resistant to memory/kinking)
http://www.afwhiseas.com/product-p/cm49-40b-a.htm

3) nylon coated kevlar
http://www.yourfavorite_kevlarsupplier.com(ic)

I am nervous about using kevlar - have not used it yet, do not want it to fray/break/creep or whatever - this is my first 2m plane. I do like light weight though!

Jetdesign

My Feedback: (8)

My new toy

MTK

Ryan,

Did you get my answer to your questions?

Jetdesign

My Feedback: (8)

I thought Patternflyer covered it above; they are both new servos but from different sources. One must be older but still in package and has all plastic gears.

corch

My Feedback: (1)

THAT'S going to put you over on weight......won't even ponder the dB penalties either

Jetdesign

My Feedback: (8)

!

Jetdesign

My Feedback: (8)

I ran into Dave Brown in the book store the other day. I had my AMA hoodie on so he said something. I just think that's so cool

Jetdesign

My Feedback: (8)

Can anyone recommend a good building stand?

MTK

Why did your cross grained balsa crush? Did you not use hard points?

I use 1/4" x 5/32" carbon tube hard points. The blind nut is mounted on adonut of 1/8" a/c ply and backs up against the carbon tubing.

I made teflon covered kevlar 10 years ago and am still using this stock today. All cable types need a simple rule followed at the contact points....make sure you round off any hard edges on steel ferrules and threaded rod holes. Kevlar has never failed while ss has....

Jetdesign

My Feedback: (8)

I just went to re-gear the two servos - I got nylon gears for the MG, and a metal output gear for the old 3517. It is easy to remove the nylon output gear, but it leaves behind the bearing and what looks like something else. Don't want to pull to hard - so I put the nylon output gear back on and find it's pretty easy to just spin it around the shaft.

What holds the gears to the pot shaft??