Speed 400 Pylon Racing - 1 vs. 2 wing servos - RC Groups
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Sep 02, 2002, 08:39 PM
RCGroups Author
SoarNeck's Avatar

Speed 400 Pylon Racing - 1 vs. 2 wing servos

Hi all,

Some gents in town are looking to get a S400 pylon racing league going in town, and I've decided to take part. Since the basic requirements are a Graupner 6v motor (timing adjustable), 8 cells, APC 5x5 prop and 150 sq" min wing, there aren't many kits available ready-made. That's a good thing...I'm designing my own!

I'm pretty much designing to the minimum specs (152sq", Vv=0.018, Vh=0.438), but I've decided to run a 5.9% thick airfoil (which I can't describe further...secrecy you know ). As such, it's effectively flying on ~130 sq" of MH30-style wing.

Anyways, the question is this: do I use one or two wing servos? With one, things are simpler, but differential is harder to set. With two, I can try things like snap-flap, and landing becomes easier with spoilerons. Is it worth the added hassle?

Also, could some pylon guru's explain how they set aileron differential? Do you want an axial roll, or is some adverse yaw useful seeing as there aren't rudders on these models?

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Sep 02, 2002, 09:18 PM
Gambler-AG DLG Designer
Allan Wright's Avatar
I'm no expert, but weight is your enemy. An extra servo is dead weight on a pure racer.
Sep 02, 2002, 09:49 PM
Registered User
See you at the races. I will have my own 150 sq in racer (MH20 8% thick) ready to challenge you.

I wouldn't add the complexity of two wing servos unless your secret airfoil needs flap to turn fast. Differential is not necessary and axial rolls are lower drag than asymetric rolls.
Sep 02, 2002, 09:52 PM
RCGroups Author
SoarNeck's Avatar
Bring it on! Good to hear that there are quite a few people interested. Any idea how many might be showing up?
Sep 02, 2002, 10:36 PM
Registered User
This is an interesting question. I've seen several people modify the servo mount on the VIP racer (not a Sp400 racer, similar) and mount 2 HS55's side by side, giving them differential and spoilers for landing. The VIP drops like a ROCK with spoilerons.
Sep 02, 2002, 11:42 PM
So tired
JJEXP's Avatar
I thought for speed 400 pylon, you could only use 7 cells, not 8. Correct me if I am wrong
Sep 03, 2002, 12:20 AM
RCGroups Author
SoarNeck's Avatar
Could be...I'm not sure. These are local rules I'm talking about here, since there's no minimum area requirement in FAI that I know about.
Sep 03, 2002, 08:37 AM
Registered User
These are our local rules so we are allowing 8 cells and mandating a larger model than the Stinger and most of the other all moulded models so they fly fast but are still usable as sport models.

I know at least six people are building for the first event. There may be many more...
Sep 03, 2002, 04:34 PM
Registered User
Neil Stainton's Avatar
They sound like excellent rules. The idea of using 7 cells for competitions is mad - just a relic from the distant past when good chargers were very expensive.

I hate 7 cell packs because of the odd number of cells makes the construction so awkward. And the performane of an 8 cell model is much better...

Sep 03, 2002, 09:56 PM
Registered User
Flying Cat's Avatar
I recently removed the second servo from the wing of my Python. Originally, I installed the second servo so I could slow the plane during landings.

But once I had more than 5 landings under my belt with this plane, I found out that I did not really need the spoilerons, so to save weight my Python now has a wing with only one servo.

Good Luck on your races,

Flying Cat
Last edited by Flying Cat; Sep 03, 2002 at 09:59 PM.
Sep 04, 2002, 09:12 PM
Caution:Makes sharp left turns
Troy's Avatar
Your rules sound a lot lot what some of the 1/2A pylon gas guys want to do. 150sq" min. wing and limiting the engines to bushing (stock) .061s and 25% fuel. Though, I think they want a minimum weight of 15 oz. The idea is to have airplanes that are big enough for most guys to fly and keep it fast enough.
I like the 8-cells as well. Do you guys have a wing loading or min weight rule?
Sep 04, 2002, 09:53 PM
Registered User
Originally posted by Troy
Do you guys have a wing loading or min weight rule?
No and No. See the related thread https://www.rcgroups.com/forums/show...threadid=59858 for a full listing of the proposed rules. I think a competitive model will have to be quite light though.
Sep 04, 2002, 10:01 PM
RCGroups Author
SoarNeck's Avatar
I wouldn't personally be in favor of a loading rule, since it would limit creativity a little.

On a related note, I think I can get this little critter in just a hair over 13 oz...should move pretty well at that weight.

I only wish I'd heard about this earlier, since I'll barely have time to flight test. I haven't done any racing for about 10 years...I think I'll name my racer "Ziggy"
Sep 05, 2002, 01:06 PM
Caution:Makes sharp left turns
Troy's Avatar
Originally posted by DaveSawers

No and No. See the related thread https://www.rcgroups.com/forums/show...threadid=59858 for a full listing of the proposed rules. I think a competitive model will have to be quite light though.
Yah, I suppose you'd penalize yourself for being heavy.
Sep 05, 2002, 04:33 PM
Registered User

Bigger than 150sq. in., room for 8 cells, not another heavy composite ARF, finishes at 13oz... Seems like I've heard of an airplane that fits this description before. www.fastcomposites.com