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        Build Log Contra-prop ESM Spitfire Mk. XIX build

#1 scatsob Oct 08, 2011 04:00 PM

Contra-prop ESM Spitfire Mk. XIX build
 
THIS
http://img194.imageshack.us/img194/1...spitfire72.jpg
PLUS THIS
http://img440.imageshack.us/img440/1420/17164.jpg
EQUALS THIS
http://img202.imageshack.us/img202/4...reprxixps8.jpg

I have ALWAYS wanted to do a contra prop Spitfire and this motor just came up on HK. It will be a dual 3 blade setup (I already have the props from a previous failed Mosquito project, 16x10 MA's) on 6 cells each. It will probably be a while before I start; I just got funding from my CFO and need to order everything. For anyone that has built similar sized ESM planes, would the EFlite 120 retracts work on this? Iím trying to not have to do a LADO conversion on the ESM retracts to save a little money.

#2 TripleW Oct 08, 2011 04:53 PM

Cool Scott! What size is that motor?
I think the E-flites are too small. You might call Troybuilt and check on the status of the electric retracts that are coming out for the ESM birds. maybe you could go with stiff legs till they come out.
http://www.troybuiltmodels.com/categ...cessories.html
Later, Walt

#3 scatsob Oct 08, 2011 06:58 PM

The motors are 50mm diameter, sameish size as the motor on the Extra I always flew at riddle. On 6 cells with the props I have it should be over 3Kw combined on a 15lb bird, so over 200 watts/lb. Roughly the same as as two .75's It'll scoot.

I will probably order the plane from TBM so I will ask on the retracts. I read somewhere the retracts as they sit take something like 45 seconds to close???? Thats not good.

#4 Orvis Oct 08, 2011 07:27 PM

Subscribed! Looking forward to your build.
Regarding the E-Flite retracts, if your model weighs in at around the suggested flying weight of 13 lbs, I think they should work ok.
I used them in my 120 size Dewoitine which weighed in at around 12lbs and they worked beautifully.
However, if the Spitfire weighs any heavier, as most ESM warbirds do when completed, then that may prove to be a different story. Might be worth a try though just to see what these puppies can handle.

Cheers,
Peter

#5 TripleW Oct 08, 2011 07:32 PM

From what I've read these ESM birds end up heavier than the spec. Your probably looking at a 8 or 10 cell set up for this bird.
You might skim through this thread for info, since it's similar in size. Or PM Mpope1 for help.

http://www.rcgroups.com/forums/showt...&highlight=esm

#6 scatsob Oct 08, 2011 07:43 PM

2 Attachment(s)
Orvis-I have read in other threads that people are using them on 12lb planes. There is a thread from a loooong time ago (2006 :) ) where the converson weighed in at 14 lbs with a sound system on 6 cells so I think thats right where I'll be. And that was with a pound of weight in the nose that hopefully I wont need due to the heavier motor.

Walter-No 10 cells, I cant afford that many HV ESC's :). Itll be 2x6cells, one 5000mAh battery per motor. And speaking of P-51's, I would love to do a Precious Metal 51 but I dont have the glassing skills or the time to make it look good. And in all fairness, I was in love with the contra prop Spitfires first. God I wish someone made a large kit for the Supermarine Sea Fang.

#7 Vik_ Oct 11, 2011 02:42 AM

subscribed
I would be interested to see some ground tests of this motor with props

#8 TripleW Oct 11, 2011 03:26 PM

This looks like the one.
http://www.hobbyking.com/hobbyking/s...dProduct=17164

#9 scatsob Oct 12, 2011 06:46 PM

well everything is ordered :). The only thing I didnt get yet are the retracts. TBM told me that they will be getting a lot of new ESM electric retracts next month, including ones for this plane, so I will call back them. Hopefully they have fixed the you-retracts-will-be-up-by-the-time-you-want-to-land problem. And hopefully the come with nice aluminum rim wheels. I guess I could always get LADO's but man are they expensive.

#10 TripleW Oct 12, 2011 08:20 PM

Cool Scott! This is gonna good.:popcorn:

What props are you gonna start with?
You can always do retracts after the maiden if you have to. Lighter too.
Walter

#11 Chad Veich Oct 13, 2011 12:14 AM

Subscribed to this one, very interesting. I'd like to do a Martin Baker MB-5 and/or a Red Baron RB-51 at some point, both of which need the contra-prop system to be really "right".

I had the pleasure of seeing PS890 perform at Chino before it went overseas and was converted back to a stock XIX. A truly wicked sound!

http://i23.photobucket.com/albums/b3...tXIXa_redo.jpg

http://i23.photobucket.com/albums/b3...tXIXb_redo.jpg

#12 scatsob Oct 13, 2011 08:05 AM

The props I have from my Mossy project are 16x8 three bladders. That's good for now but MS has 16x10 three bladders that I will probably end up getting for a little more performance.

#13 scatsob Oct 14, 2011 07:09 PM

Everything is shipped now :). Just need to wait a week or so to get my package from China. Plane should be here Monday or Tuesday.

#14 V2rider Oct 15, 2011 12:42 AM

Quote:

Originally Posted by scatsob (Post 19581503)
The props I have from my Mossy project are 16x8 three bladders. That's good for now but MS has 16x10 three bladders that I will probably end up getting for a little more performance.

I think I've read on here somewhere on these setups you want to run a higher pitch on one motor than the other. 16x10 and 16x8 would probably be a good match.

#15 scatsob Oct 15, 2011 12:35 PM

Got the plane!:) Man that was fast, I ordered it on Thursday afternoon. Hopefully my motor doesnt get held in customs too long.


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