pahtreek

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Well, I started putting the WING center section together tonight. I have most of the ribs in, just have to figure out a few things on how I am going to mount the steel straps on the top and bottom main spars for the outer wing panels to attach to the center section for the 3 piece wing. It shouldn't take much, it just has to be stronger that the spar. It does not take that large a strap to do that.

1BadF14

Can you show detail of how you mount the steel straps

pahtreek

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I am going to try and draw something up this week. I will post it when I am done .

pahtreek

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Well,
I have been very slack on posting any pics. I have been working on the 3 piece wing, and how best to join them together. This is what I came up with. It is a one bolt per side attachment using a 4 1/2" long 1/4-20 bolt. I also used metal spacers and inserted them into the spars to help reduce the chance of splitting or breaking the spars. I also took some pliers and broke off the "teeth" of the t-nuts. It left just enough to bite without going too deep into the spars. I also took a pic of where I cut a piece of aluminum and epoxied behind the spars where they come together in the upper gull part of the center section.

So far it has been tricky, I had to do it a couple times to get the bolt to exactly line up with the t-nut. I could have used a screw in insert instead of a t-nut, but with the "long" threaded area, it gives a lot of area to epoxy and should never back out. Plus it was less intrusive and I was able to drill a much smaller hole in the spar than if I used a threaded insert. I inserted the spacer in the bottom spar, and ran the drill up thru the spacer into the upper spars which I had not yet glued in. I then tapped the t-nut, and tested the bolt several times to make sure it lined up before gluing in the upper spar.

I forgot to note that the smaller bolts are just 10/32.

I think this will work really well, I hardly added any weight other than the bolt and a couple spar doublers. Should be much stronger than the spar, and will not develop any play over time.

The 3rd from last pic shows some blocks that I am gluing in for bolt alignment and also to align the top steel strap as it gets inserted into the center section wing. Also, I just placed a piece of wood to show how I will lock up the box. It will be 1/8" 5 ply plywood which should make everything very strong.

pahtreek

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Progress... I cut the ribs and got the outer panel framed up in a few hours... Starting to take shape and look like a Stuka!! I think I am going to use 1/8" aircraft ply for the inner sheer webbing, lite ply for the middle, and balsa for the outer rib bays. I made most of the ribs out of 1/8" balsa.

pahtreek

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The right wing connection is done. I couldnt be happier with it. It is 10x stronger than the spar at any point and one bolt attaches the right wing to the center section. I epoxied a 1/4" steel pin into the top steel strap. Then epoxied the whole assembly into the wing. The area that I shaded with a pencil is where the pin is. You can also see the lines I penciled in so I knew where to glue it so it lines up with the top spar. I think this is much stronger and lighter than a wing tube and all the ribs I would have to beef up. I just have to epoxy the aircraft ply back sheer plate on the back to sandwich it all in and make it even stronger.

This is my first real build thread in 10yrs, I made a couple for my 101" stuka and p-40, so I am not sure what I should show or take pictures of.

pahtreek

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Wow, that 3 cylinder four stroke 150cc engine would be purrrrrfect! If our economy wasn't such a disgrace and the dollar held it's own, I might be able to save up for one of those Kolm engines! If it is $3,500 euro's...that would be about $4,700 us dollars. RIDICULOUS!!!!! Arrgh!

pahtreek

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I started working on the landing gear. I think I can make them for about $30, but knowing me I will make them a couple times as I refine the design. I am still not sure if I want to use compression springs or a pull spring on the back (I posted a cad pic earlier in the post). I wish I could take credit for the idea, but Slick Larson came up with it years ago on a smaller stuka he had for many years. Worked great. I am also looking on the web for manufacturer's of small compression shocks. I am amazed at how well some of the large RC trucs handle being dropped from table height. They just stick to the ground, no bounce. So I think that would be the best solution.

It took me about 1minute to weld the door hinge on to the wire. I bought a cheap wire feed welder from Harbor Freight (about $150) and it really comes in useful for this kind of stuff. I just wish I bought the unit with the optional gas feed so I could weld Aluminum.

Since the tires are hidden on the stuka, I will probably go buy some $10 8" tires from harbor freight or another hardware store. They do make some that are not too heavy.

I will post some more pics as this design changes into the final product.

I also took a pic of the first attemp at the landing light. I think I am going to replace it with something else so you see the reflective "funnel" instead of a black ring. It doesnt look very scale to me, although it would be really bright. Just took it off a flashlight.

pahtreek

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Well, I cut a short slot in the side rails and slid them over the door hinge and welded it up. I am really happy with everything so far. I have about $8 bucks invested. Also, I found some 1lb tires that hold 300lb at harbor freight for $9 bucks a piece. Take that Sierra! lol

pahtreek

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Has anyone welded thin aluminum? I am not happy with the muggyweld that I used to put the canopy together. I am thinking about using jbweld, because the more I research about either having someone weld it for me, or buying a $175 TIG welder at harbor freight, the more I am starting to think that welding thin aluminum is REALLY hard.

Any ideas that dont involve a lot of money??? The one quote I got from a local welder was $140 for him to weld it. At least if I buy a welder or gas torch system, I can use it again and again when I need to weld Aluminum.

pahtreek

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Now that I have the gear partially built, I couldnt resist putting it all together to get an idea of the size. Maybe I am getting used to working with it, but it doesnt seem near as big as it seemed when I started.

WacoNut

Hi Pahtreek,
Been watching in the background. Thin aluminum is really herd to weld properly. I work in the aerospace industry and we have a couple certified welders where I work and they are using some very expensive TIG welding gear. They do weld aluminum for me when needed. How thick is the aluminum on your canopy frame?
It takes a very small dia. tungsten electrode and a fine control to weld thin aluminum. You may even need to weld it in a purged booth to get good results. Let me know how thick it is and I will ask my welding guys if they would like to try it. Maybe on a sample piece just to see how it works 1st.
If you want send me a PM.
Later!!
Anthony

pahtreek

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Thanks for the offer Anthony! I sent you a PM. If I cant get it welded, the only other thing I can think of is to buy some small Alum. Angle stock and cut small pieces off and screw it all together. I just dont know how small they make taps for. It would be great to be able to use some micro screws, but again, if I cant tap the hole, it doesnt do me much good. If they do make micro-taps, I could theoretically tap the screws right into the bar (#0 or #1 micro screws), but it is only .07 thick. I would have to make a decision though, it is all together with the crappy muggy weld and is holding enough to screw it all together. If I take all the muggy weld off in the hope of getting it welded, it would be hard to screw it together if I had to try and use clamps to hold it together. Arrgh!

BeasleyBunch

If the welding doesn't pan-out...

This is a great site for all things "micro". It's kind-of addicting... so be careful!

http://www.micromark.com/

pahtreek

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What a cool site. I can see where I could spend hours looking through their stuff! I think that will be the easiest way. Plus, It will look scale and I have way more time on my hands than money!! 8-) ...I want to get started tonight though. I am going to see if these is a local place in Atlanta that I can buy it today.

-I have patience with people....not buying stuff!

WacoNut

I have to agree that some #0 screws holding the canopy together would look cool. I used over 400 #0 sheet metal screws on my 1/3 Waco, nothing better than using real hardware for attaching items.
Can't wait to see it come together.
Anthony

BeasleyBunch

Well, if you can't wait try to find a model train store... Those people use a ton of micro stuff and usually have a good supply of micro screws, bolts, etc...

samparfitt

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they make #0 taps.
I'm also into railroading and they are used in that hobby.
http://www3.towerhobbies.com/cgi-bin...R770&P=7#mults

I use #0 and 1 screws for my FG canopies from micro fasteners
http://www.microfasteners.com/self-t...-phillips.html

With thin brass and aluminum, you usually just need the proper drill bit size and the screw will self tap.
Also, with small screws, I've used a tap close to the screw pitch and it also worked.

pahtreek

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That will be perfect. I tried my local hobby store train section and they didnt have these items in stock. I will order the tap from Tower and screws from Microfasters.

I was able to finish the other wing straps so the 3 piece wing is finally done. I just had to put it all together. It has not been seeming that big till now.

Ed

Microfasters should also have the tap.

Chad Veich

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I'm not a big fan of the Stuka pahtreek but that is a very impressive build. It is sure to be an attention grabber anywhere you take it!

pahtreek

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Thanks Chad,
I am not a big fan either, but this plane is a very easy, straight forward build. No wing fillets, no retracts, can drop bombs and the canopy is very "boxy" and easy to build made this a no brainer for me. Besides, it flies like a big Cub!

...but oh, how I wish it was a Dauntless!

samparfitt

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speaking of, I enjoy dive bombing: up to 80 degree dives.
Ziroli SBD dauntless.

Ed

Nothing is more badass then the model G with 37 mm canons !

pahtreek

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Great looking Dauntless! I know what you mean about dive bombing. When I first started dropping "nerf bombs" from my stuka, I ran thru an entire gallon of gas in one day just dropping them! lol