XP-72 Ultrabolt

[Willja67]

Although I have been a member here for quite some time as many here know I mostly hang out over at pm.com. Recently Zathros invited me to come back and look around.

Although mostly I'm getting out of paper model design and into designing and building real aircraft I still have one project ongoing that some may be interested in.

At the moment Yankeeboy over at pm.com and Robert Turner are working on the last test builds (mostly to create instructions) of the XP-72 Ultrabolt that I started a couple years ago. So hopefully I can finish up my part (still a couple pages to finalize) and we can get the kit on the market. Until then here is a pic of the first test build that made it to completion (although there were several bugs left to be ironed out). Hopefully Yankeeboy is okay with me borrowing his picture.

 

[Zathros]

Oh that's a beauty!! Super Craftsmanship. Beautiful design. I hope to see more. I guess I know who's going to carry it. It's a guessing game here! I hope you stay in paper modeling, even if it's just helping out slugs like me! Please keep stopping by, you can post pic of whatever you want too. I'd love to see you project!

Robert Turner and Yankeeboy, we'd love to have people of your caliber share with us. Stop by and visit us!

 

[Willja67]

Well I finally got all the pages finished up(took 2 years). I sent them off the the test builders to critique, so there might be a few errors left to fix, but we are definitely seeing the light at the end of the tunnel!

 

[Zathros]

This is one beautiful aircraft. I look forward to it's release. Please, post it's release with a release as to where it can be purchased. Some more pics, all kinds, details, cockpit, etc. would also be appreciated. Thanks Wilja!!

 

[Willja67]

Here are a few more build pics from YankeeBoys beta and Gamma builds in no particular order.

As with past releases I will be selling through both Gremir and Ecardmodels.

 

[Willja67]

Here are a few more pics.

The kit will come with 2 versions, a contra rotating propeller version and a 4 bladed version (just like the 2 actual prototype aircraft that were built). You also will have the option of printing on metallic or plain white paper and counting every page of the kit there are 28 pages total.

In favor of getting the kit out the door I decided to forgo seperate control surfaces, but you do have the option of having the landing gear extended or not.

 

[Zathros]

Wow The instrument panels is amazing. The whole model is amazing! The fuselage looks really strong. This is one badass looking plane!!

(To be frank, I didn't know those two sold models if each other was carrying it, that may have been deliberate misinformation. not from Mike though, or Chris for that matter) seems silly. I was hoping, and still am that Mike (Gremir) will post here again.

Thanks for the pics. Any chance of seeing the real bird your working on!

 

[Willja67]

Behold QuAC/E (pronounced quackie) the ugly duckling. Obviously the first 2 are of the ugly duckling. I decided that before i tackled my magnum opus design (third pic) I needed some experience in composite construction. The name is anachronistic obviously and stands for Quick And Cheap/Easy to build. As you can see my other design is considerably more complex. I guestimate that the Ugly Duckling will cost about 1/2 as much to build and take about 1/3 the time. And even if I never finish it I will still have learned a lot about building with composites.

There is not one compound curve in this aircraft(except for the cowling).

Note: Not shown in the screen caps are the bulges for the vw engine it will eventually have.

 

[Zathros]

Sweet!. The easy inexpensive build concept is something much needed in aviation. Subaru engines are a good option for aircraft engines. Is the QUACKIE intended for the part 51 rule, or the sports category?

The second design is a beautiful looking craft. Very elegant, with some pedigree, especially in the wings. Thanks!

 

[Willja67]

I'll most likely register it under the experimental ametuer build category. Not sure yet if it will meet the stall speed requirement of Light Sport. All depends on if I can build light enough.

Regarding your earlier question about people not selling through both Gremir and Ecardmodels the goals of each distributor are not really in line with each other. If you were dead set on protecting your design from piracy then Gremir is the obvious choice, but he has allowed me to distribute through other vendors with the obvious knowledge that my models wouldn't be as safe from piracy.

 

[Zathros]

I'll most likely register it under the experimental ametuer build category. Not sure yet if it will meet the stall speed requirement of Light Sport. All depends on if I can build light enough.

Regarding your earlier question about people not selling through both Gremir and Ecardmodels the goals of each distributor are not really in line with each other. If you were dead set on protecting your design from piracy then Gremir is the obvious choice, but he has allowed me to distribute through other vendors with the obvious knowledge that my models wouldn't be as safe from piracy.

As far as those two go, that's interesting. One of those guy's works is definitely all over the internet though. GREMIR's is pretty locked down. Reality is, with a high quality scanner, and a printer, the end result is the same, though the former keeps honest people honest, and the latter is , well, away of getting your model out there.

Are you running you airfoils through any software to get an idea of what might happen? I find it fascinating that you are designing two aircraft, not that YOU are, but that you are doing it..

It would be great to see this process unfold, and document it. If you ever feel, even after the fact, of throwing up a thread about that, it would have a home here.

 

[Willja67]

Are you running you airfoils through any software to get an idea of what might happen? I find it fascinating that you are designing two aircraft, not that YOU are, but that you are doing it..

The only software I'm using is x-plane, but I'm not really depending on that for results. I've bought a lot of books on aircraft design and made some spreadsheets. The ugly duckling is such a traditional design that there is not really much need for programs. As long as I do the math I should be pretty sure of what I'm going to get.

It would be great to see this process unfold, and document it. If you ever feel, even after the fact, of throwing up a thread about that, it would have a home here.

I have a thread on homebuiltairplanes.com titled Corsair/Spitfire hybrid about the other design, but it takes me too long to do a lot of documentation for a thread. I'm just going to build it (with enough documentation for the FAA of course).

But if you come across any good deals on 65-85 hp vw's for aircraft I would appreciate hearing about them.

 

[Zathros]

Have you considered Subaru engines? the 1998 2.2 liter is an incredibly reliable motor. Montesi Auto Sales, Waterbury Ct. would be where to get an engine from.

Stratus Subaru engines are well proven. Just throwing out a suggestion, nothing more. Zenith Zodiac kit planes are using these a lot.

http://stratus2000.homestead.com/files/stratusnew/index.htm

 

[Willja67]

I have pretty much written Subaru's off in my mind just cause if I used one I'd have to do all the conversion myself (buying a firewall forward package would probably cost 2x what a vw of lesser hp would) and I'm on a tight budget (hoping the engine doesn't run over 5000).

Unhijacking the thread, I just sent a mostly revised set of parts pages to the guys doing the instructions for me. I think the model is pretty much ready, just a few little tweaks and the instructions to be made.

Oh and I added a post war Texas ANG repaint to the kit. Basically it would be the squadron show plane. I think it looks pretty cool. The OD patch is now blue with a narrow white stripe right underneath and a slightly wider red stripe below that(the tail is entirely blue no red and white stripes). Also instead of the Texas sillouhette on the tail there is a big white star. The wing tips are blue with a small white star and a white stripe inboard of that and a red stripe inboard of that.

 

[Zathros]

I thought I hadn't heard of this plane but it sure looked familiar. I thought it was called a SuperBolt. I have no idea which is right if there is a right, and it's your model and you can call it whatever you want. It sure is sweet looking! Did you make the canopy?

 

[Willja67]

I think Ultra Bolt is the correct name. When i first posted my original thread over on pm.com I called it the Super T-Bolt because I was used to the Super Corsair which was the same deal a R-2800 traded for a R-4360.

The canopy is the GPM canopy for their P-47. My testbuilder tells me that it fits perfectly on my model. But i do include a frame in the kit so you can make a precise mold and vacuform your own canopy.

 

[Zathros]

I don't know who your test builder is, but he/her, sure does a nice job! I like the first one you posted best, it is beautiful! The Wright R-2160 forty-two-cylinder liquid cooled engine they were going to put into this craft was an incredible beastly engine, until your started this thread, I had no idea there was such a thing in existence! It's worthy of being modeled itself.

 

[Willja67]

And I thought 28 cylinders was maybe a little excessive! Are you sure you have the numbers right (R-2160)? Sounds a little low for 42 cylinders.

 

[Zathros]

These are the specs for this engine everywhere:

General characteristics

Type: 42 cylinder radial engine. 6 rows, 7 cylinders per row
Bore: 4.25 in (107.9 mm)
Stroke: 3.625 in (92 mm)
Displacement: 2,160 in³ (35.39 l)
Length: 96 in (2438 mm)
Diameter: 35.5 in (901.6 mm)
Dry weight: 2,400 lb (1088.6 kg)

I don't know this absolutely, I've never seen or counted the cylinder heads, but that's what seems to be listed everywhere. Imagine the torque on something like this? Could you imagine the torque, you'd have to have a really big rudder.!

 

[Willja67]

Sorry to doubt you I went and looked it up myself after posting. It's interesting that the later versions of the R-2800 were able to put out about the same hp. Although the R-4360 weighs 1000lbs more it also puts out 1000 hp more, so I guess the power to weight ratio is about the same. But with the 4360 the cooling mechanism is built in, with the 2160 you still have to put in a radiator. And i bet the R-4360 is probably more reliable as well.