kingaltair

My Feedback: (4)

This one is for you Evan. I thought that I had remembered Helen talking about a Nimbus III, but I couldn't remember for certain.

From her last e-mail, I need to revise a statement I made back in the first post about the TBX-1 being Tom's last design. If Nimbus III was designed in October of 1965, and flown in 1966, that would make IT the last design. It also shows that Tom continued to fly R/C models into 1966, and got out of the hobby roughly the same time as Ed Kazmirski, (and about one year before my first plane...(finished in Brett colors...if anybody cares).

I'm pretty sure the colors on this plane were the same as Apogee and Perigee...only the Nimbus-1 and Nimbus II had the other colors.

Finally, the color scheme of the Nimbus II is settled as being white and maroon, which is what I first thought before I started second-guessing myself. The following is directly from Helen's e-mail:

Ah, the Nimbus III. I got the drawings out and discovered it was drawn in Oct. 1965. I measured the wing and it is 72 inches, as opposed to 66 for Nimbus II. Tom didn't fly it much, mainly because he finished building it in February and I started taking my flight training March 5, 1966. He continued flying models that Spring and Summer, but not to the extent of previous years. He was going for his commercial license at the time and there were not enough hours or spare time. Actually, I had four lessons and we bought our Cessna 172 before the end of March. Of course, Tom had waited since 1949 for me to be ready to get in the air.

The Cirrus came about because Tom wanted to try Proportional. Don Brown was on the FAI team with him and was coming out with a new system he wanted Tom to try. It was early 1963 when he designed it,I think. I measured the wingspan and it is 73 inches. It had retract gear and brakes. The DeeBee (I think it was called) had several breakdowns and he became frustrated and went back to Perigee and Apogee for the season.

Now to (answer) the current email: I don't know why he went for (Nimbus) III. The wing has the same aileron as the II, but the wingspan is larger. As you know, I can't get to the fuselages, but I imagine there is some variance there.
For the Nimbus II, the color is white and marroon, I don't know why. Obviously he preferred the old clear silkspan over the solid one since Apogee and Perigee, etc. carried on the old tradition, (of lt blue and dark blue).

Duane

pimmnz

Right, well, I guess you have got your work cut out for you now, there's Nimbus 3 and Cirrus plans, not forgetting Simla of course. You might as well forget flying this winter, just concentrate on getting this stuff finished...
Evan.

kingaltair

My Feedback: (4)

I'm not planning on building all three of them anytime soon. If I'm someday able to get a chance to look at the plans for Nimbus III, and Cirrus, it would be very interesting to determine the differences between them. A larger Nimbus, (or a MUCH LARGER Perigee sounds great to me...I like larger planes (as you know).

These new discoveries are very interesting to me...like you, I didn't even know there was a Nimbus III, or a Cirrus. It's "cool" to me to learn about these new planes. I bet they'd fly great on proportional.

About the Cirrus...I'm wondering about the difference in design. That fact that the Cirrus was "designed for proportional" .....I wonder what design elements Tom changed because of proportional radio alone. The Cirrus has a 73" wingspan, (the largest of all Tom's planes we know of, and about the same as Nimbus III). I wouldn't think wingspan would have anything to do with type of radio would it? Factors such as dihedral, rudder angle, and perhaps control surface size might be the things that change the most due to radio type, correct?

Any ideas?

Duane

pimmnz

Probably right Duane, the only thing I can think of is possibly R/C gear size and weight being the biggest size driver. Remember Taurus is a 70" wing, so N3 at 72 and Cirrus at 73" isn't that much of a size step. By '64 and '65 .60 engines would be common too...not forgetting that Tom was right in the middle of Altairs, Simlas, et.al so there was plenty around, even then, that was saying 'bigger is better'. Best guess would be that with better engines, and a time when experiments were going for bigger airframes, Tom would not want to be left out, radio type wouldn't be much of a driver for the other things either, more likely, in Toms case, styling would have more effect on airframe design than radio specifics.
Evan.

kingaltair

My Feedback: (4)

OK...BACK TO THE PLANS

Here are some views of the wing in no particular order:

Free Bird

Here's a few more progress pics of my Perigee restoration. These shots were right after the masking was removed. Still need to do the trim on the fin/rudder. That will happen tomorrow followed by a light wet sanding and clear on Monday. It's looking more like a Perigee!

FB

kingaltair

My Feedback: (4)

LOOKING FORWARD TO SEEING IT ALL TOGETHER. All those little "swoops" look difficult to achieve.

crankpin

My Feedback: (15)

Very nice, Freebird !

Crank

Free Bird

Let's put it this way Duane, it sure was a challenge! And they're far from perfect.

Crank: Thanks! I'm glad you like it....

FB

WEDJ

FB - OMG! F'ng awesome!

Are we still on for Jr Skylark on Monday?

Free Bird

Thanks for the kudos WEDJ!

Sorry to say that I can't make it on Monday.[&o] I have to work tomorrow [:@] (Sunday) and do the family thing on Monday. We still have a few weekends before the Octoberfest to get'er done!

A little update on the Perigee restoration. All of the graphics have been applied to the fuselage and wet sanded out. The airframe is now ready for the clear coat. Here's a few pics. Now back to your regularly scheduled programming.
FB

kingaltair

My Feedback: (4)

Hi everyone

I've been pretty busy on a "bunch" of projects lately, and have not been able to keep up with working with the plan pictures. Now it's time to get back to business on the TBX-1 plans. So far we have looked at the T-stab, and the wing. Now we move on to the most challenging part of the plane IMO....the fuselage.

As a reminder, the fuselage blueprints on the existing TBX plans are the most faded, aged-looking, and the darkest. As you will quickly see, the rather complex plans are made more complicated because the color scheme is drawn over the blueprint, and is the easiest thing to see. It is possible that Tom used THIS COPY of the blueprints primarily to work on the color design, so you have to mentally look through it.

Due to the "miracle" of the modern computerized "darkroom" however, I am able to enhance somewhat the quality of the pictures I've taken of the original. Remember, all pictures of the plans were taken of the original blueprint, (not the copies I've made), in an effort to get as much detail as possible. I've tried to provide the largest picture size possible in an effort to give you the largest, most life-sized drawing that I can.

We will be starting at the rear of the fuselage, (although there are a couple of photos with "detail" drawings that I haven't quite figured out the full meaning forI'd like some additional insight into those detail drawings). You can see how the rudder pushrods are designed. As we move forward you can see the rib patttern for the vertical fin, and finally the wing side view. This was the picture thjat proved that the wing was built upside down, and that the TBX uses a semi-symetrical, (or double convex wing for Evan's benefit).

One thing I haven't determined yet is the incidence relationship between the wing and the horizontal stab. Maybe we can determine that from the pictures we have; I'd like some help with that please.

BTW-Something to look forward to...after we finish with the plans, we have some new exciting things to discuss thanks to Helen Brett.

Duane

pimmnz

That's BI-convex Duane! You do like keeping us on tenterhooks, but seriously I would really like a copy of the Nimbus 3 plans, should they see the light of day.
Evan.

kingaltair

My Feedback: (4)

That's BI-convex Duane! WHATEVER

As for what's coming, I think there is a better than even chance that two previously unknown Brett designs, (except to local RCCD members), will indeed come to light...including plans.

Duane

RFJ

Not relevant

kingaltair

My Feedback: (4)

I've continued to work on the photos of the TBX fuselage. One of the first things you notice when you look at the profile of the plane is the extreme amount of downthrust used by Tom. When you refer to the original plan, you can see that the downthrust in the model was NOT the result of adjustments made during flight tests, where more and more thrust was needed to allow the TBX to fly properly. The downthrust (6 degrees by my quick check), was drawn into the plan from the start. Coupling that with the BI-CONVEX wing, I would imagine the plane would fly well inverted. I would appreciate some general opinions of the fuse plan as it relates to the TBX's imagined flight characteristics.

Earlier I talked about how we tried to remove the hatch behind the engine to see exactly what was in there, but it had fused in plane and we didn't want to force it. It turns out there is a second, smaller fuel tank immediately behind the engine. I remember seein Tom work on the fuel pressurization system by pumping a bulb. It seems, at least to me, there wasn't a pump, and the system relied on air pressure to move the fuel from the main tank to the smaller one where normal fuel draw would take over.

Again on the fuselage plan, (in addition to the wing), you see a mark for C/P, (which I have presumed to mean "center of pressure". Look a couple inches behind the C/G location for that little symbol.

The fuselage plan is very "busy" with lots of seemingly extra lines that Tom must have used for reference. It's hard for me to sort everything out. Add to that it is the faintest and darkest of the plan sheets, and the color scheme is superimposed on top of everything. Please, I could use use some help here.

Free Bird

Interesting that Tom used a pressurized 2-tank system. I would think that with today's wisdom, a pump or the use of header tank with muffler pressure would achieve the same results as Tom's setup. Or to simplify things, just use a normal tank setup behind the firewall. Only question with that would be what affect that would have on the CG.

As far as the fuselage plans go, it's kinda hard to make out some of the "stuff" out in the pics. It sure is a lot of fun though looking through them and trying to "think build" what Tom had accomplished.

FB

kingaltair

My Feedback: (4)

I agree that the C/G would probably suffer by moving the tank. The more I fly SPA, the more I like the idea of the fuel tank over the C/G so you don't have to make corrections during the flight.

The highly swept wing means the C/G is "way back there", so putting that much weight toward the front would be a problem. Tom used a ST .56, (a relatively light engine). I'd probably put a .60 or .72 FSboth of which are heavier, and would require weight shifted toward the rear. I think a modern pump system of some sort would be the best solution.

The actual plans ARE somewhat easier to read than these photos, but at least it gives you "fans" out there a feeling for what the plans look like.

I'm more used to using a radial mount such as the Dave Brown for mounting the engine. Traditional "rail" motor mounts were used in all planes of the period, but I think it makes it harder to build, and get the thrust setting correct. You can see the firewall isn't very sturdy by itself to support the engine, so either the firewall set-up would need to be modified, or we'd need to build with the rails according to plans.

Preview-Cirrus and Nimbus III plans are on route from Michigan. These previously unknown designs, (at least to me) will be covered next. Unfortunately, Helen says there are no vintage pictures of Nimbus III. This was a time when Tom was winding down his R/C flying activities, and taking pictures of Nimbus III probably wasn't a priority. She is still looking though. Perhaps some day I'll be allowed to re-assemble Nimbus III to do its own photo shoot.

Tom's daughter Sheryl has agreed to provide her own take on her Dad's hobby which I am looking forward to.

Duane

We have other "goodies" coming as well...in the form of bio material on Tom, and photos from Helen's collection

kingaltair

My Feedback: (4)

Cirrus and Nimbus III plans arrived today safe and sound. These two previously unknown plans are drawn on vellum(sp) and are in perfect condition. They will make very nice plans. The plans are in the same format as the others, and look like 18-inch scrolls.

Duane

pimmnz

Now you're talkin! As for the derogatory comments about mounting beams, be a bit careful there lad. These beams project back into the fuselage structure and really tie the front end of these models together. Nor is aligning them much of a problem, everyone used to know how to do it...
Yes, two more Brett models. I can see the hangar growing.
Evan.

kingaltair

My Feedback: (4)

This is what I said above about the traditional rail motor mounts:

I'm more used to using a radial mount such as the Dave Brown for mounting the engine. Traditional "rail" motor mounts were used in all planes of the period, but I think it makes it harder to build, and get the thrust setting correct. You can see the firewall isn't very sturdy by itself to support the engine, so either the firewall set-up would need to be modified, or we'd need to build with the rails according to plans.

It was not meant to be "derogatory", just factual. Personally, I haven't built a plane that way since I was a teen ager, (40 years ago), so it might be a little more of a challenge for me. I never said it wasn't as strong...with the rail motor mounts, you don't need a thick firewall. If I eventually decide to build one with the radial mount I'm used to, (which I probably won't because the plane wasn't designed that way, and the changes would be major to do it), I'd have to do the things I mentioned above.

Helen called last night to make sure the plans arrived safe and sound, (which they did). She had sent some 8mm movie material to Chuck Winter for his video work, and they apparently were delivered to the wrong address.[X(][&o] They will probably turn up soon, but it's a worrisome thing to have 45+ year-old movies unaccounted for, even for a short period.

Duane

kingaltair

My Feedback: (4)

Here are a couple of the pictures that Tom's daughter Sheryl e-mailed to me the other day. My best guess is they were taken during early 1962 as Tom was building his travel crate for the 1962 FAI Internats in England.

When looking at the open crate picture, do you think the one on the right is the "oldest Perigee on earth". That seems to be a popular viewing angle.

Duane

RFJ

Don't know about that, but which is the Perigee and which is the Apogee

Ray

kingaltair

My Feedback: (4)

Apogee is "on top" or furthest away, or "left"...you can barely read the name on the left fuse panel.

It was supposed to be a subtle reference to a "previous discussion".

Free Bird

We know where the "Oldest Perigee on Earth" is and there's no question about it's origin!

FB