Hangar 9 P-40E Refurb

Hangar 9 P-40E Refurb

Postby Dale » Sun Oct 27, 2013 10:12 am

And it starts again!
IMG_7494.JPG

P-40 036.jpg

My father's (Wayne) Hangar 9 P-40 .60. Perhaps can be written as Hangar Queen P-40.
This was bought several years ago 2nd hand from a chap in Hamilton minus engine.
Currently has a pumped OS91 4st, however has only had a couple of flights on it since buying, and that is largely due to retract issues.
The retract issues are on the path to redemption, and after a request from him, we'll give it an overall tidyup.
The colour scheme is awful. For a start, its the AVG Flying Tigers (like all other P-40 ARFs), it is in horrible shades of dark colours, its glossy, and its iron on. So here goes the latest un-ARF'ing thread.
This model is long out of production, with no spares available, so a request to you guys, if anyone has any parts, or bits left of one of these in the shed somewhere would be keen to purchase. Please reply here or send me a message at dale_bradly(at)hotmail.com
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Re: Hangar 9 P-40E Refurb

Postby Dale » Sun Oct 27, 2013 10:15 am

As factory supplied, it has mechanical retracts, driven by the typical centre mounted retract servo. Ive spent ages playing with this, trying different servos, messing about with linkages, removing slop etc and eventually gave up on it, determined to make something more reliable and robust. The only flights (2 or 3) it has had have been on the mechanicals, and each one required adjustment afterwards, so these drove us nuts.
Some while later, decided to try Wingspan retracts offerings.
These failed on the bench, and cant extend the leg, so have since been removed the manufacturer contacted for comment. I await their reply, which i don't think is coming.
Unfortunately, this left a bitter taste in ones mouth, as these are rubbish. Well, the rotating ones are anyway.

Image

An exhaustive hunt began for the "perfect" P-40/Corsair retract.
-Electronic
100 deg extension
Robust

And nowhere have i found this item.

However, i do have a set of Sierra Precision air retracts, so these are going to be made to fit.
DSC06286.JPG

So i began that process by stripping the wing. And in case anyone is wondering, i took 118g of iron on covering off the wing
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DSC06356.JPG
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Re: Hangar 9 P-40E Refurb

Postby Dale » Tue Oct 29, 2013 4:12 pm

Wing is in pretty good shape, somewhere had previously had a knock to the leading edge which was repaired.
Have sheeted the previously open wing bays ready for glassing, followed by a once over with the filler and sandpaper.
DSC00502.JPG

Ailerons were held in with CA fuzzy hinges, so was a doddle to cut these off. A quick sand, and then recovered with Solartex. (P-40 has all control surfaces fabric covered). Rehinged with Hingepoints.
Next stage is to mount the retracts and subsequently the distinctive retract housings and gear bays, followed by the underwing central fairing and cannon.
Once all this is fitted, i'll glass it all in place and paint.

Image
Pic of a real one from random web search interwebs (http://peoplespoliticsiii.yuku.com/topi ... m809Pl9s5s)
Note the u/c and centre fairings. (and also for those who aren't familiar with it, why retracts are so hard on these!)

Colour scheme has yet to be decided.
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Re: Hangar 9 P-40E Refurb

Postby Dale » Mon Feb 17, 2014 8:26 pm

Back into it!
Since i last posted, I've moved to the Mainland, so this (along with most of my model stuff) has been in storage for a while. Settled down south now, so unpacked it and got back into it.
Spent a while finding all the bits, looking it over and getting my head back into the project.
First thing i then did was made some guns for the wing.
Here's the real one:
Image
(Kiwi Aircraft Images, Motat P-40)
Note how they are located in the lower half of the leading edge.
I found some 5mm brass tube, and some 12mm pine dowel, rounded the end, bored a hole through it, and then glued into a matching hole in the leading edge, using a little jig to hold things in place.
Mine, during some fairing and filling:
Image
The only major build task on the wing is the centreline fairing (as in fullsize pic above), but might put this off for a bit, and glass the wing first, then come back and deal with the retracts and various fairings.

I've also got into the fuse, which will take a bit of work.
Image
during the stripping phase. Note the awful wrinkly covering.
15 min later after using and abusing the missus' hair dryer:
Image
I have to say, i much preferred the build quality of the "chinese" World Models airframes over this "american" airframe. (Of course, it isn't made in the US). Just seems the wood quality, and even the design is pretty average, despite their brand marketing hype.
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Re: Hangar 9 P-40E Refurb

Postby Dale » Sun Feb 23, 2014 6:58 pm

Haven't done much real work on it this week, other than fill, sand and seal the top side of the wing. Will likely glass it soon.
Where i have put some effort (and money!) into is getting stuff sorted:
There are several areas of this airframe i am not happy with for various reasons, in no particular order:
Cowl: Looked "wrong", and genuine replacements are not available.
Tail group: "sheet" surfaces (as seen in previous pics) looked wrong and made it look too toy-ish
Fin/rudder shape just looked off
underwing plastics (belly fairing, gear covers etc all looked wrong.
Canopy broke during removal and again original can't be sourced.
Wing fillets are a "maybe", haven't decided yet.
After many hours of interwebs research, what we are going to do is turn it into a Top Flite P-40!
Well, sorta.
The Top Flite Gold Edition Kit is very very similar in size, so i'm going to obtain, and fit the pertinent bits from the TF kit to sort out these areas. (e.g. there is only 6mm difference in width between the TF and H9 firewall widths).
On order, but several weeks away, are a pair of aftermarket fibreglass cowls (i.e. better than factory) for the TF P-40, from http://www.fiberglassspecialtiesinc.com/
As part of this, i've been spending a bit of time doing some CAD to plan things out. One thing that is really helpful is TF provide PDF templates of their diecut parts, which i then imported into cad software, and scaled to the model size, along with threeviews of the real thing. Allows me to pretty easy see where things are/should be etc.
I won't bore you to death with screens of autocad drawings of ribs and formers, but it has proved quite handy.
Image a sample, here i was playing around with the TF rudder shape on the fullsize outline. Here's the same outline with the current H9 fin/rudder: Image
I'm not into hard out accuracy, if it looks like the real thing during a flypast, that's good enough for me!
As well as the cowls, have ordered some parts from Top Flite, so until these get here, there isn't a whole heap of woodwork i can do yet, but will continue on with the wing.
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Re: Hangar 9 P-40E Refurb

Postby Dale » Sun Mar 02, 2014 5:03 pm

Have glassed the top of the wing with 25gm cloth and epoxy.
Then turned the wing over and got busy underneath.
To fit the Sierra retracts in, we needed to adjust the mounting blocks. The original mechanical units were top mounted, (i.e. the mounting plate was fitted to the uppermost part of the retract (when up the right way), deep in the wing.) The Sierras are bottom mount, thus needing to be fixed to the underside of the wing.
Some hardwood blocks were fitted, sitting on the original mounts; the top spar, the adjacent ribs, and just about anything else nearby.
These were then trimmed to put the retracts where i wanted them.
This was a bit of a challenge, needing to incorporate all the various angles, rotations and extensions.
The end result is they are in and do everything they should, but the tradeoff is that when extended, the legs stick out (when viewed from front/behind) parallel to the wing underside's dihedral, and not vertical as per scale. (I think to be correct they would only rotate something like 83°, not 90°) I could have gone the other way, had then stick out vertical, but then they would be at a funny angle in the already small wheel bay and look odd in flight. I'll restate my belief that "perfect" retracts for P-40's this size do not commercially exist.
Image
Wheels are 4" Robart Scale, look excellent, if a little heavy.

Once that was sorted, got to work on the fairings.
In the pic above, you can see the wheel well. This is a new pair of H9 items, but in the interests of durability and looks, these have been faired and glued in, and will be glassed in, so there won't be any edges or coming unstuck.
Re leading edge fairings, Check this pic, on the left is the original H9 gear fairing, on the right is a TF one, I likes this much better! To the rear is the other TF one unassembled. TF might be slightly too big, but looks about right.
Image

Have not yet cut gear slots, Might consider doors in these (the real one has two doors in each fairing). Probably not though.
These fairings will get also get glued, blended and glassed in for seamless jointing.
Image

One other thing as part of this fitment, i had to pretty much remove the lower spar to allow the retracts to fit in. To replace this, and still leaving room for the gear, i cut a slot along the spar either side, and have epoxied and 3mm steel wire into it, across the gap. With it missing, the wing was pretty solid, but now with it in, it's even stiffer. Can be seen as the line between the retract and wheel well.
Image
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Re: Hangar 9 P-40E Refurb

Postby Dale » Sun Mar 16, 2014 7:32 pm

In the last couple of weeks, i have made up both the retract fairing covers, glued, blended and glassed them in. Have then started giving the wing the overall weave fill and smooth. This time i pasted a pretty thick coat of nitrocellulose filler all over, (also known as spot filler, glazing putty, knifing compound and no doubt other names). dries quick and reasonably hard enough, then sands off real easy. I have previously used a second coat of epoxy, and other guys have used car bog. (I've tried car bog previously, but wasn't happy with it.)
(Image

During the week, a nice package arrived. The missus took one look at the size of the box and asked if "that is another plane". No, just parts for one.
Image
I had placed an order with the Great Planes/Tower/Topflite empire for some parts. They sell individual parts and die-cut sheets for their models, and at pretty reasonable prices. (i.e. a sheet of die-cut parts is only 2-3 US$). As i had previously converted their die-cut patterns to CAD at the correct size i could have cut them myself the old fashioned way, but still would have had to buy wood anyway, and i needed to get a canopy, (i.e. pay for shipping) so just got the whole shooting match from them. Interestingly, some of the parts are die-cut, and some are laser cut, i guess they are slowly moving into the 21st Century.
Obviously i also grabbed the Top Flite plans to put it all in perspective. Just spent an hour studying the plan! The Top Flite instruction manuals are a download from their website, so now know all about the TF kit, and can now relate this to the H9 items sitting on the workbench. (and the white plastic items in the pic are the panels inside the cockpit rear windows, another "maybe" item.)

So the first item to build is the new tailplane. Kit building is so much fun! In about an hour, i had it framed up.
Image
Is really interesting to note how different in shapes they are. You would think that when building a model, you'd start with a scale outline. Apparently not. The tailplanes have diffferent aspect ratios, and moreso different leading edge sweeps. Similarly, here's the rudders pre assembly:
Image

So will carry on assembling the new tail surfaces over the coming week. Once that is substantially done, with then cut out the original ones and figure out how to join the two brands together.
Since taking the rudder photo, i realised one other thing that really looks awful: The tailwheel. If you look back at the previous pic of the fuse, you can see it hanging (in typical cheap'n'easy ARF style) off the rudder, wheres the real thing it is well forward, can see it on the edge of the plan photo. (somewhere in the vicinity of the servo cavity on the rear fuse).
Will i do anything about that i am wondering...
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Re: Hangar 9 P-40E Refurb

Postby Dale » Mon Mar 24, 2014 1:16 pm

I'd forgotten how pleasurable building from a kit is as i put together the new tail feathers. Construction seems to consist of gluing large pieces of tree together, then planing and sanding to shape, so there is quite a bit of wood(weight) in these.
Image
Compare on the above pic, the new bits and the original fin/tailplane assy.
Still got a lot of sanding/blending of the bits.
Have cut the original tail section off the fuse, to enable work to start on getting the bits together. I won't be gluing them in though until the front end is well on the way though, so they aren't getting in the way. Sheeted surfaces will be glassed, and the open structures will be covered with SolarTex textured iron on covering, just like my Harvard.
Deserves a test assy though!
Image
Image
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Re: Hangar 9 P-40E Refurb

Postby Dale » Sun Apr 13, 2014 7:12 pm

Been ages since i updated, so here's a bit. I have done a bit lately, got several jobs out of the way.
First thing i tackled was the wing fairings.
The P-40, like most low wingers that had speed as a design criteria, has substantial wing root fairings. (I believe this is because there is a large amount of interference drag caused at the wing/fuse joint, so the fairings are to try and minimize this somewhat).
The T/F kit has substantially bigger ones, so after a quick check of some photos of real P-40's to check they are in the ballpark, i got busy.
Here's the Top Flite plan against the H9:
Image
So whipped them up, usual story of bottom sheet shaped to suit wing, rolled top parts. Has 3 small ribs on the inside, and the front 3rd or so is solid balsa sanded to shape.
Here's a better comparison:
Image
!!!
Next thing i did was a new tailwheel.
The lower rear fuse is a solid balsa block, so fitted some ply to it inside and out as a bearing surface, and whipped up a new leg, and fitted a 1.25" wheel. Currently is castoring only, if it becomes impossible to steer on ground, might link it back to rudder by springs. As the rudder servo is immediately adjacent and external, linking it directly is going to take too much thinking.
Image
Next thing i got onto was the not insubstantial underwing fairing.
Again, adapted T/F's item to suit. Is builtup, with about 5 ribs under the sheeting.
A shaped solid block behind the wing completes it.
Image

I then opened out the gear extension slots. I had thought about some form of gear doors, but quickly gave this idea up. As (relative) simplicity and reliability are two of my goals, gear doors didn't fit with this, and surely this would be more weight again.

Because she now has a full set of new feet for the first time, need another test assembly!
Image

Have been toying with making it a "K" version:
Image
(Kiwi Aircraft Images http://www.kiwiaircraftimages.com/pages/a92p40a2.html)
The main obvious difference is the fillet on the fin. I wonder what the punters think?
P-40E: (imagine the gap filled in obviously!)
Image
P-40K:
Image

I have made up the platform that the tailplane will sit on, but this is not fastened yet, and won't be until after the front end's makeover.

And the last bit:
You all looked at the pic of the underwing fairing, and wondered what that dark item on the centreline was. Well, its for this:
Image

One of them things you purchase once thinking you'll use and never do:
For those who don't know it, is a self contained bomb and release mech from Hobbyking and elsewhere.
Image
I stripped the working parts out of the pylon assy, and made it fit into the wing fairing. Is servo operated, making it work, and be accessible/repairable had me stumped, but eventually just semi-permanently mounted the servo in the front part of the underwing fairing, and joined it to the slide mech via a short bowden cable.
Image
1:1 P-40's use some horrible system of mounting underfuse items on multiple struts, but i just wasn't going there. Also briefly considered hanging one under each wing, which would have been simple, (just use the whole factory bomb system as is) but then thought about more weight again, would there be drag issues if only one dropped etc etc so one on centre it is.

I expect the new cowls are only a couple of weeks away, so when they arrive i can get into the front end, which should go pretty smoothly. Once that it sorted, then i'll fix the tailplane and fin, then head toward glassing the fuse.
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Re: Hangar 9 P-40E Refurb

Postby Dale » Thu Apr 24, 2014 8:24 pm

Easter was last weekend, and as i live nearby, I spent a good part of the weekend at Warbirds over Wanaka.
Amongst all the good-ery that was there, i spent some time checking out a "real" P-40, ZK-RMH, formerly NZ3009, which is a former RNZAF aircraft. Although it now wears Chinese markings, it has previously been in RNZAF colours.
I also spent some time chatting with the pilot, Stu Goldspink, which was interesting and enlightening.
Image

Came home full of enthusiasm, and got into the next bit, which is the canopy area.

I had to replace the canopy, as the original H9 example didn't survive being removed. The Top Flite example was of course the go, so i cut this out and decided where to put it.
This quickly led to having to sort something else first, which was the rear canopy.

The P-40 has in interesting canopy, in that the rear fuse behind the pilot is scalloped, and then glassed over, presumably to allow some form of rearward view. (This is a decade before the widespread use of the bubble canopy).
Check this pic: (Kiwi Aircraft Images)
Image

The original matching area:
Image
You can see the inward rolled area, and the screw holes show the outline of the original H9 canopy. The pencil lines are the new TF canopy outline.
This would be a bit arkward making the two brands meet at this point, so i got around this by cutting out them scallops, and fitted the TF window recesses.
Image
Note the turtle deck is sheeted foam. (to simplify mass production i presume).

Then glued in the TF cutouts with my favourite modelling glue, Gorilla. (Cause it's strong, light and fills gaps!)
Image

And the result looks like a P-40!
Image
Image

This has created one relatively small issue, in that the fuse immediately in front of the canopy isn't high enough, i.e. the front edge of the canopy isn't actually sitting on the fuse. This needs to be built up so the canopy fits properly, but this isn't a big issue, as this area is about to get an extreme makeover to make the TF cowls work, which should be underway in the next couple of weeks.
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