Avaiojet

I'm starting this thread for "any and all modelers" who have interest in the RCM Article and plans that were published in 1964 about the aircraft Bamboo Bomber.

It's called all kinds of things. Cessna T-50, UC-78. Crane, Bobcat, Bamboo Bomber, Skyking Songbird.

The model is drawn 64" in span which is about 1/8 scale? It's certainly a great set of plans, I have them, and I wish anyone building this model, from these plans, absolutely the best.

You now have a thread where you can discuss this fine sport, semi scale model at 64".

I'll be on this thread shortly because I'm going to compare the actual scale outlines with the RCM plans of 1964. Could be interesting?

Charles

zipman

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Greetings everyone,

I will start this post by saying I have had the 1964 RCM UC-78 plans for about 40 years. How's that for holding on to a dream. I love multi-engined aircraft but was always hesitant to build one with glow power especially with the modified tanks these plans required. It wasn't until electric power was applied to r/c models that I again got the urge to pull out these plans and start planning a build. I know there are a lot of you out there that have the RCM plans and I am curious why you have not built it yet.
If you have, please post your success, your build comments, your modifications, your concerns and some pictures that will encourage others to move forward with their build.

To start the discussion moving I scanned in some comparisons pictures of specific parts of the RCM plan vs a Paul Matt 3-view. There may be more discrepancy in a picture than what I noted. If you see others please comment on it. I took basically 7 areas that I felt were out of scale outline with the Paul Matt drawings. I will post a few at a time so we can focus our comments on them.

The first pictures compare the nose profile. I can see a definite side difference but I am having a hard time with the top view. Tell me what you think.

Thanks for looking

Stan

I have to reload the pictures, they were too big.

Avaiojet

Stan,

Thanks for those shots! Which ones are the Paul Matt drawings?

The nose has obvious differences. Pick one? Not a good joke. Both could be drawn incorrectly.

I got a feeling the Paul Matt drawings are of a "model airplane" and NOT the actual aircraft, as I expected.

Tell me this isn't so?

If that is the case, I will hunt down "factory" drawings.

I know this thread is for a semi-scale model at 64", but where are you taking this?

Are you planing on altering the RCM plans to improve the scale outlines?

I can actually trace and outline any line on any drawing with my PC program. The smaller the drawing the better actually.

Although I'm not building the RCM model, I will still use those plans as a construction guide for the larger, not by much though, model I'm building.

My goal is "accurate"scale outlines for my model.

Are you making changes to the RCM plans?

Charles

zipman

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Charles
The Paul Matt drawings in the pictures are the smaller scale drawings. Matt's 3-views from what I have heard are pretty accurate. I hope others will verify that.

I am doing the comparison for anyone who wants to build the RCM plan and decide if any inaccuracies in the scale outline can be improved with minor modifications. I am not planning on dissecting every inch of the airframe since I do not know how accurate the length, width and height is. If it does not matter or the mods require major work than building per the plans will still result in a very flyable model. Again you can apply the Duck theory, if it looks like a duck, flys like a duck, must be a duck.

I have not graduated to CAD yet, some day. It is something to consider using the RCM plans as a base for improvement. I plan on minor out line changes and not a redraw of the plans.

Avaiojet

Stan,

I just realized, from your photo, I have the Paul Matt drawings. Or I should say only plate 2 of 2, on an 8.5 x 11. Bummer.

However, I do have them coming in the mail, hopefully soon.

First thing I'll do is trace the outline. I'll then be able to do an "overlay" in any size over other plans. Actually not difficult.

I did notice his drawing of the "nose" of the aircraft is accurate. The fuselage area after the metal nose cone is stratght on top and not arched, as the RCM plans.

Hardly worth the mention.

Charles

squeakalong

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Received a nice package from jhunter today regarding the 1964 RCM UC-78 plan/article. Within was the following "heads up":

T-50/UC-78 Bobcat 1/48 scale plastic model will be offered by Czech Model (Stock No. CM4819)
Decals and color painting guide for Sky King's "Song Bird" and USAAF UC-78 from 1943.

Soft landings.

Joe

Avaiojet

For those that may have interest?

http://www.hobbylinc.com/htm/czm/czmcm4819.htm

Charles

zipman

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YOO! Too much money for such a small model. I guess Czech Models must be paying Cessna some big royalties for the use of their name, that or The American Dollar is worth nothing. For $43.00 I can purchase all the wood to build the RCM UC-78. A 1/72 plastic model is also available on EEE-Bay for about $28.00 if anyone is interested. I wanted one for documentation, but now I will wait for Mike James to finish his 3D Bamboo Bomber project then everyone will have available the most comprehensive documentation available on this aircraft.

GO Mike.

Stan

zipman

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Charles,

If you do this would you be so kind to post a PDF in 1/8 scale so us RCM plans builders could use it to decide on the out line changes we might like to make?

Besides the nose correction, i want to reshape the wing tip, vertical fin/rudder and the side view of the nacelle.

In addition to this, I would like to add an additional former so I can attach the wing with a leading edge dowel and wing bolts at the trailing edge. Finally to allow for retracts, I need to redesign the structure of the nacelle. Did anyone of you address any of these mods on your plans? I would especially be interested in the nacelle redesign.

Here is a picture comparing the side view of the plan to the 3 view, plan has the red arrows.

Avaiojet

Stan,

Thanks for your interest and participation.

Unfortunately, I don't think you'll find too many guys interested in building the Bobcat?

Your RCM plans, you have a good eye. I mentioned in my opening Post my reasons for not having interest in those plans, as far as "scale outlines." Certainly the RCM plans can be corrected, especially with both of us picking out areas that need change.

Even with changes, those plans can still be used to build the 64" model.

It actually doesn't take that much more time to build a larger model. It may cost a bit more in the long run, but having a larger model has many benefits.

I'm sure I'm building at 84" or 1/6 scale.

I've already drawn retract gear in 1/6 for this model and will have the parts list available when I finalize my findings and put a set together.

I don't want to use this Thread to promote my model, so I'll stop trying to convince modelers to build the 84" one.

But for anyone interested in a 64" scale model with improved scale outlines which are not offered on the RCM plans, I believe Stan and I can come up with a more scale outline and point out the areas that need change and attention on those plans.

I imagine I can save my outline scale drawing as a PDF file, however, it may not be sized for the RCM plans. This would mean that modelers would have to print it out at the proper scale, then they can do an overlay.

We can talk more about this. I don't have the outlines prepared anyway.

I'd like to see more active interest in the "Songbird."

Charles

aerowoof

I also have had the plans for about 30 years and is on my to do list I even have fibeglass nacelles and the canopy for them.I also would like to point out that the plans may not be off as much as you think as the plans could be based an a different 3 veiw or different model of the plane.I have a few documents which resemble the rcm plan more than the paul matt drawings tho there are more pictures of planes that resemble the matts.

Avaiojet

Aerowoof,

That could be a possibility, but I doubt it. The areas that are "different" on the RCM plans are that way because that model was drawn as a semi-scale model, so no one would expect it to be totally scale.

The Bobcat did undergo engine changes, however, these changes would only require cowling changes, and not the rear design of the nacelles or the fuselage nose. Stan has found these differences and pointed them out.

This one has three blade props! The cowlings are sealed?

Nothing wrong with a semi-scale model at 64" in span. Or a change in the RCM plans to offer a better scale outline.

You actually have a good start, with the "extras" that you have. Stan has those parts also.

Be nice to know exactly how many guys have interest in the Bobcat, not to mention this aircraft's many other names.

Charles

jhunter

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http://richard.ferriere.free.fr/3vues/bobcat_3v.jpg Aerowoof, these might have been used on the RCM plan.

squeakalong

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Aerowolf: where did the fiberglass parts and canopy you have for the RCM plan originate from, and, do you know if they are still available? Thanks.

Hey, John..good to see you around these parts!

Soft landings.

Joe

Props4ever

Hi Guys,

Sorry for getting into your thread here but i have been looking at this thread since it started and i can't figure out why this aircraft is called "Bamboo Bomber", i am sure there must be some history to this nick it's given, can anyone share some light on it. Thanks in advance...[8D]

Sam

Avaiojet

Sam,

Thanks for the question and the interest.

Simply put, the aircraft was nicknamed the "Bamboo Bomber" because of the "extensive" use of wood in the construction. I don't believe any of the wood was actually Bamboo?

Charles

Props4ever

So to say same as how Hughes Huge/Massive Hercules H-4 flying boat was nick named as "Spruce Goose"...

Thanks Charles for this piece of history and information, appreciated.

Sam

squeakalong

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A note in case anyone wants to order the RCM UC-78 plan: I placed an order for this plan a few days ago (along with another 8! plans) on the RCM website. Selected plans, gave all required information and waited for the confirmation on my order. The webpage hung up so I tried callling the 800 number that was on the website...no one answered the phone []. Next day I sent an email to them and was told they never received the order [:@]! Where the h#@* did all that information go to then ? Anyway, if you want to order RCM plans you need to either call them (and hope they answer the phone), fax them, or email the order and payment information directly to them. They say they are working on an updated website to come in the future. For now I'm going to wait for the new secure website before giving out all that personal information...again .

Avaiojet

I said I would do an update when I received the Paul Matt drawings. I scanned them into my program then enlarged them to the same scale as the RCM plans.

The RCM plans show the wingspan as 65.5" I'm sure this is a plan wing and this measurement is without the dihedral?

Anyway, for better or worse, I settled at 65" measuring with the dihedral.

I won't give you the measurements that are on the plans because you have them.

The following are the measurements I obtained from the Paul Matt drawings when I scaled them to a 65" span:

Keep in mind the "room for error," because of line thickness and my 65" span measurement. I could have used 65 1/4" or something else?

Using 65" wingspan, I got the following...

Fuselage length, 50 7/8

Fuselage thickness 8 5/8

Fuselage height 9

Nacelle diam. 5 3/4

Nacelle length top 14 3/8

Nacelle length bottom 15 1/2

Cowling diam. 5 7/8

Cowling length 3 1/4

Wheel diam. 3 1/2

Tail wheel diam. 1 7/16

Prop. 12

I hope this is of some value.

Charles

Avaiojet

Paul Matt disappointment?

Well not really, and honestly, no one's perfect. It is only model airplanes. Can't loose track of that.

However, I do notice that not one of his nacelles measure the same, in any of the areas he has them drawn. Three I believe. Add then divide by three? A possible solution.

Certainly not that big of a deal.

So, I'm going to do some re-thinking on this? The quick thought would be to use the largest nacelle measurement, seeing the things are big to begin with. Bigger wouldn't be as noticeable as smaller. Yes, I know, just the opposite of some things.

As Arnold would say, "I'll be back."

Charles

Avaiojet

I mentioned that my Paul Matt drawings had differences. That's not quite true. Paul, I apologize. I found these differences, because I was using a drawing I thought was a Paul Matt. What a dope I can be. Incidentally, my covering will be silk and dope. Good time to mention this.

I'm on track for my scale outline in "vectored" line art. This photo "is" the Paul Matt drawing, but I've done a "line" overlay. The colors of the lines can be changed easily. I changed colors to make the drawing more interesting. You can also see the drawings I made of scale retract gear. A few of them. I'll get a photo of the line art with the Paul Matt drawing removed.

Thing is, my scale outline drawings can now be sized easily to any scale. After a scale is determined, construction drawings can be added. Also in vectored art form.

The scale I decided to build this model at is 7.45. That is, every measurement taken from the actual airplane will be divided by 7.45. This will give me an accurate measurement for the model.

Seems like a lot of work, and it is.

However, in my opinion, having a model with "really close" scale outline appearances is important. At least to me.

Next will be the wing drawings. My wing drawing outline will be done over the Paul Matt drawing and I will use this line art as a diagram, to be used by the foam wing cutter. Whoever that will be? Yes, I will have 2 degrees of washout, just like the actual airplane.

zipman

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Charles,

Lookin good. You are on a roll keep up the good work. I like having a front view on the plans which the RCM plans were lacking. I see your new scale size of 1/7.45 will result in a slightly larger version with a wing span of 67.5 inches. Also looks like your planned fuse construction will be a traditional stick built structure assuring a lighter airframe. The retracts look very scale like and would look great electric powered.
I like it.
I have an original set of the Wing Manufacturing electric retracts which may inspire us in that part of the buld ( way ahead of their time). I will take some pictures and post them to show how they operate. They use a jackscrew design and some micro switches.

Keep it coming.

Avaiojet

Stan,

Thanks for the reply and interest.

Yes, the scale I'm using will bring the span to 67.5", which is perfect for many engine choices and the fuse will be built up. Plus this gives me a healthy 3.5" main wheel.

My retracts, which I'll concentrate on after the 10 of Jan, will operate with "Lado" supplied electric activators.

I'm familiar with the Wing gear you have. I could use the jack screws on my 1/5 scale Grumman F3F1. Drawings are in the works and are almost completed. The F3F gear drawings are completed. Wanna trade that gear? Remember, I do model graphics.

Unfortunately my wife and I, plus two dogs, leave for FL on Saturday. I won't be back till the 10 th of Jan. So there won't be much happening with the Songbird Thread.

I'll move fast when I get back, making or acquiring all the necessary items I need in the construction areas. This includes the foam wings.

BTW. The foam wing thing isn't carved in stone. I can and have constructed many built up wings.

In fact, here's a couple of photos of my crib.

Charles

buzzard bait

Thanks Stan and Charles, I hope you keep this up. I love the UC-78 and have had my eye on the RCM one for decades without doing anything about it. I did think it didn't look quite right, and I think the nose error is the reason. Very helpful to have that pointed out. Noses are very noticeable, on airplanes as well as people!

My other hang-up is the landing gear. I just don't have the skills to make retracts for this. I think shock absorption is important too. I wish someone would do a metal working book for airplane modelers.

Charles, you have one of the coolest and most inspiring workshops I've ever seen!

Keep up the good work, guys.

Jim

Avaiojet

Buzzard Bait,

There's another Thread on a T-50 or Bamboo Bomber build. It's actually mine.

http://www.rcuniverse.com/forum/m_81..._1/key_/tm.htm

I'm building one at 84".

In fact, I plan on doing an update shortly on my progress. This will be glass parts, foam wing and retracts. Not to mention scale outlines as best as can be.

I plan a second one at 72". I'm doing the math on that one now.

Thanks for your interest.

Charles

Gotta love these old colors and schemes.