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Scale Build-Off- ParkflyerPlastics 95" span P-40

wilmracer

I build things that fly (sometimes)
Mentor
#1
So with Wilsonman's blessing I'm going to enter my winter build into the build contest. Full disclosure... I already have it in another build contest and started on the model in early January. When I found out there was a build contest going on here as well I thought this forum may have more interest in it. It is a BIG foamy built from a short kit.

The short kit, including plans and vacuum formed parts, is available at http://parkflyerplastics.com/cart/index.php?main_page=product_info&cPath=24_26&products_id=529

I also picked up a set of CNC cut formers and ribs from kenscadmodels.com

Since I've already started I'll just do a dump in the first few posts of the progress to this point.

To start the build an assembly rig is put together from electrical conduit. This holds everything in alignment and make assembly a LOT easier.

Formers are aligned and wing skins applied. Cap strips are applied and rough shaped and the cutouts aft of the cockpit are cut in.
 

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wilmracer

I build things that fly (sometimes)
Mentor
#2
The cowling is formed from 1/2 foam layers, lined with balsa for a clean seam, and 4-40 retaining bolts are added.

The cowl is attached and the forward fuse is rough shaped.

Additional material for scoop is added and the hatch is cut out with a hot wire.

Hatch is lined with balsa and additional shaping is done.

Retaining latch for hatch added. Starting to look like a warhawk!
 

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wilmracer

I build things that fly (sometimes)
Mentor
#3
Wing construction needs to be done next before continuing with the fuselage. You need the wing done to work on the wing saddle and fillet area.

The original plans call for BIG Robart retract units that require cutting the main spar and rely on the retract unit housing to transfer the load between the severed sections of spar. I modified the plans so I could use a smaller electric retract without cutting the spar.

So plans are transferred to 48" sheets of foam, spars, ribs, and pushrod guides for the split flaps are installed. I also installed wiring tubes and the air tubes for the spektrum telemetry Pitot system. The Pitot tube wont be 100% scale, but it is in the scale location and is functional, so that's cool :cool:

Wings are then sheeted, leading edges and wingtips are added, and wingtips are lined with balsa to resist dents and dings.

Once everything looks right the wings are glassed with 2 layers of 0.5oz fiberglass. Still a lot of work to do but I want to move on to the wing saddle area and get the fuse glassed soon.
 

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wilmracer

I build things that fly (sometimes)
Mentor
#4
This brings us up to where I'm at today. The wing retention plate was installed and the holes for the bolts were drilled in. I'll likely recess the bolts all the way to the ply plate they sit against. The other option is to put a few additional layers of heavy glass on that portion of the wing, but even with that the foam underneath could deform under high loads or if the bolts are over-tightened.

I plan to start the wing saddle area this weekend. Still a long way to go with the build but I'm targeting a maiden mid-spring.
 

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wilmracer

I build things that fly (sometimes)
Mentor
#5
miscellaneous...

The only other work done so far has to do with the cockpit interior and pilot. I wanted something special for this aircraft.

The pilot figure is from iflytailies.com. I'm doing a lot of customizing with it, and the BIG thing was that I ordered a 3D printed version of my head at 1/4 scale from thatsmyface.com :cool:

Also started detailing the cockpit interior and instrument panel. It isn't 100% scale but I think it will look good enough to fool most people
 

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wilmracer

I build things that fly (sometimes)
Mentor
#8
Nice. Whats your power setup?
Haven't finalized the power setup yet. An eflite power 160 will fly it, and a power 180 might work a bit better. Another guy is building one with a Scorpion S-5535-160 on 10S.

I'm going to wait until I get a bit closer and have a better idea of AUW before I commit and pull the trigger on the power setup. Only requirements for me are 3 bladed prop (doesn't have to be scale) and solid performance. I'd like top speed to be in the 80s-90s but I'm more concerned about having enough thrust to fly with confidence.

The prototype came in at 17lbs, which is a little over half of what similar sized Zirolli models come in at. It should fly like a parkflyer even at 20lbs AUW.

I'm hoping to get it dialed in before flite-fest 2015 :)
 

nerdnic

nerdnic.com
Mentor
#9
Great work so far! To get that kind of speed out of something that big you're gonna need more power than a 180, though. A 180 with the suggested 20x12 prop would give you in the range of 50mph. Using a 3 blade is going to be even slower.
 

wilmracer

I build things that fly (sometimes)
Mentor
#11
Great work so far! To get that kind of speed out of something that big you're gonna need more power than a 180, though. A 180 with the suggested 20x12 prop would give you in the range of 50mph. Using a 3 blade is going to be even slower.
Yeah. The power system is still up in the air. There are some MONSTER systems out there that would do it. I may have to settle for a lower top speed, but we'll see.

I'm open to suggestions on power systems. Of all the aspects of building designing power systems is one I'm not super experienced with. Typically I just find proven solutions, but for this one I may need some help.
 

willsonman

Builder Extraordinare
Mentor
#12
Glad you could join us. I fully expect some great results here. There is plenty left to do on this bird. I read Kieth's entire build and yours is already looking quite the part.
 

wilmracer

I build things that fly (sometimes)
Mentor
#13
A bit more work done. Wing fillets are rough shaped and the first coat of filler added. There will be more shaping done once this cures and hopefully on to glassing before too long.


Web050.jpg Web051.jpg Web052.jpg Web053.jpg Web054.jpg
 

wilmracer

I build things that fly (sometimes)
Mentor
#16
I just realized I haven't even printed my plans yet. :/
Get to it :D

My secret weapon on this build is that my wife moved to Germany for the first half of this year for her job. I have the house to myself until July and frankly I'm a bit stir crazy already. Lately it isn't unusual for me to be in the shop 4 or 5 hours a night. I actually had to put an alarm clock out there to remind me to go to bed :eek:
 

wilmracer

I build things that fly (sometimes)
Mentor
#18
This is an excellent build! How many hours do you have into it so far?

Btw, this is my first post :)
Welcome Jakers! I'm still very new to the flite test forums too.

I'm not tracking the build hours exactly. A conservative guess would be 20-30 hours of actual build time. Plenty of additional time researching, making profile templates from a plastic model kit to be sure the lines are close, and generally screwing around.

Someone could build faster if the stuck exactly to the plans.
 

wilmracer

I build things that fly (sometimes)
Mentor
#19
Still cleaning up the wing saddle area. A bit more work to do, particularly on the underside where the belly pan on the underside of the wing meets the aft fuselage. Getting closer though and hope to be glassing next weekend.

In the meantime though I have spent a bit bashing together the mechanics for the pilot...

 

jamboree1

Active member
#20
Still cleaning up the wing saddle area. A bit more work to do, particularly on the underside where the belly pan on the underside of the wing meets the aft fuselage. Getting closer though and hope to be glassing next weekend.

In the meantime though I have spent a bit bashing together the mechanics for the pilot...

Too cool, name him Lt. Dan, he has no legs