Thread Tools
Sep 14, 2006, 07:31 AM
Super Cub fan
RAFguy's Avatar
Thread OP
Question

What servos and RX for Peck J-3 Kitten?


Hi guys, it's been a while. I'm building the Peck Polymers J-3 Kitten, designed by Thayer Syme and have a few questions. Wondering if anyone has built one and I need reccomendations as to equipment. If I'm reading the the instructions correctly, my target weight should be 60 grams. I will use the motor Thayer reccomends, the M20A 5:1. One option is the Falscon Breeze Block that includes two 2.1 gram servos and a built in RX. It will fit fine in the fuse, plus get a BSD single cell speed control. Now to raise the big question. Can I use the Blue Arrow 3.6 Gram servos with a Berg Mini Stamp RX and a Pixie 7P speed control? Or would this combo be to heavy for this 24 inch bird? Also what size Li-Po is anyone using in this kit.

I so far have the tail feathers built and one side of the fuse, it will look nice in its tissue covering. I have not picked a scheme I like yet, I may just stick with the yellow tissue that came with it.

Any insight would be great!

Cheers
Jim.
Sign up now
to remove ads between posts
Sep 14, 2006, 09:32 AM
Gravity is a harsh mistress.
Tim Wolff's Avatar
Toss one of the BA 3.6g servos on a scale and you will see that they weigh ~4.4g each. Even at 4.4g ea. they will prob be ok for the Kitten. You are in 2-cell territory with the pixie 7p. The battery will be determined first by the current requirements of the power setup and then by how much weight you need to balance the model.

The Falcon setup on a single cell would be ideal for indoor and dead calm outdoor flight. It should be light enough to be a real floater. I would use the Falcon or a similar setup if I were building this plane. It sould be doable well under 60 grams (I hope).

I also recall a report that the wing ribs were cut incorrectly in the kit. It was in one of the print publications, but I'm a bit fuzzy on which one and exactly what the problem was.

How about some pics of the progress?
Sep 14, 2006, 09:40 AM
Super Cub fan
RAFguy's Avatar
Thread OP
Thanks Tim, will do on the pics!
Sep 14, 2006, 09:52 AM
Team 30 Micro EDF
Mike Taylor's Avatar
Allow me to throw my two cents into this...

The Falcon Breeze is a real favorite of mine; I suggested that as a product a while back, and they came through I have a wad of them in different planes, and they are excellent pieces of gear. They have good range, don't get interference hits, and are as easy to mount as you can get. Costs have plummeted since they spooled up for mass production, they weigh much less than the early prototypes, and the quality is even better than before.

They do have one drawback for larger models, and that is their short throw. You will need to make sure that you have a slop-free control linkage. Also, when you make the control horns, make several holes in them so you can tune the surface movement to suit your stype of flying.

As far as the motor goes, I will bow to Thayer's opinion and experiences with it, but single cell driven M-20s for me have had the power adequate for about 1 to 1 1/4 ounce models. Over that, performance start dropping off rapidly. You could up the output with a 2nd LiPoly (and use the 2-cell ESC, of course) and the cells don't need to be very big - 90s or 145s would do fine. I feel for a 60 gram model an N-20 would be more appropriate and one would add just 4 grams to the total weight.
Nov 06, 2007, 06:40 AM
one game away...
PerfectStranger's Avatar
I've read up as much as possible on this model and am ready to start on it. I would like opinions on my chosen power system...sufficient or insufficient? I'm excited about this model. Never used tissue before and I'm looking forward to it. Between this forum and RCMW there is some darn good information on these little motors and the M20's...seems to all come from G. Johnson. Thanks for your testing Gordon!

Estimated AUW 60g +/-
Plantraco 4 Ch Servo Receiver
N20a ULV geared 4.2:1
4-5" prop
Blue Arrow 2.5 gm Servo (X2)
Single lipo cell - I have many variants to choose from

Thanks,
Matt
Last edited by PerfectStranger; Nov 06, 2007 at 07:41 AM. Reason: forgot to add prop
Nov 07, 2007, 08:10 AM
one game away...
PerfectStranger's Avatar
I've read up as much as possible on this model and am ready to start on it. I would like opinions on my chosen power system...sufficient or insufficient? I'm excited about this model. Never used tissue before and I'm looking forward to it. Between this forum and RCMW there is some darn good information on these little motors and the M20's...seems to all come from G. Johnson. Thanks for your testing Gordon!

Estimated AUW 60g +/-
Plantraco 4 Ch Servo Receiver
N20a ULV geared 4.2:1
4-5" prop
Blue Arrow 2.5 gm Servo (X2)
Single lipo cell - I have many variants to choose from

Thanks,
Matt
Nov 07, 2007, 12:38 PM
Flying Models Plans
Matt,

Here is some new data on my prototype. It was out of commission for a while, but I refurbed it for the JR Indoor Electric Festival this last weekend.

I still have the original motor, prop and ESC in it. New are the receiver and servos. The night before I left, I installed a Spektrum AR6100 receiver stripped of its case and pins. (1.82 grams) I also replaced the Wes-Technic servos with a pair of Falcon 1.6s. I trimmed the connector of one end of the lead, and soldered directly to the rx board. I also just grabbed the closest battery that would fit, an Etec 2S 250mAh pack.

You should have no trouble making your weight goal. Mine was 59.5 grams flying over the weekend.

I would recommend a test frame to see about the tissue. A light coat or two of clear Krylon should be all you need to seal it, and the test frame will let you see how much weight you are adding before it matters.

Thayer
Nov 07, 2007, 05:00 PM
one game away...
PerfectStranger's Avatar
All good ideas. Thanks. Yours sounds like a winner, especially with SS!

Matt
Last edited by PerfectStranger; Nov 07, 2007 at 05:56 PM.
Nov 07, 2007, 07:02 PM
Flying Models Plans
i don't know about a winner, but it was the first. At under 2 grams, I think the stripped AR6100 is a good match for models in this size range. At this weight the model did well in the golf dome, but can still do well in a light breeze outdoors.

Thayer
Nov 11, 2007, 05:42 PM
one game away...
PerfectStranger's Avatar
Check this out if you would. I don't want to double post.

https://www.rcgroups.com/forums/show...07#post8530907

Thanks,
Matt
Nov 11, 2007, 05:55 PM
Flying Models Plans
Sorry for the mistake Matt. I should have labeled the tail surface ribs as 1/16x3/32.

Thayer
Nov 11, 2007, 06:20 PM
one game away...
PerfectStranger's Avatar
No problem at all. It's my first one and thought maybe there was a reason for it...though I couldn't think of one.

Matt


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold Radio system for PECK-POLYMERS new J-3 Kitten hobbyshopguy Aircraft - General - Radio Equipment (FS/W) 6 Sep 10, 2005 06:52 AM
How do you know what servos to buy for a plane? FlyingMist Beginner Training Area (Aircraft-Electric) 8 May 22, 2004 07:39 AM
numbers for Herr J-3 Cub wing? mu2freighter Scale Kit/Scratch Built 7 Dec 02, 2003 11:22 AM
WTD--wanted plans/ instructions for piper J-3 cub derailed Aircraft - Electric - Airplanes (FS/W) 0 Jul 30, 2002 09:45 PM
What servos and battery for Zagi? Tin Pusher Beginner Training Area (Aircraft-Electric) 3 Jul 15, 2002 10:43 PM