RE: SIMLA BUILD THREAD
 

The red aircraft is a Gazariator that was in kit form by Sterling in 1975. The one in the picture I scratch built from a set of plans that I had left over from building the kit in 1975. It was Sterling"s 60 size version of their 40 size Fledgling kit. I haven't flown it yet, but back in 1975 the Gazariator was a great flyer and very stable.

Bill

RE: SIMLA BUILD THREAD
 

David,

The first aircraft is an original. I was just sittimg around with an extra OS 46 AX and decided that I wanted a sport/pattern plane for that engine, so I sketched a picture of what I wanted and then drew up plans for it. The air foil is fully symetrical. I basically drew a center line on the aforementioned Sterling Fledgling airfoil and mirror imaged the top half to get the ful symetrical airfoil. And since the Fledgling was also a great flyer I used its dimensions to create the over all results on my original. I have not flown it either, but I am sure it will do well when I finally do get to fly it.

Bill

PS- Along with the OS engine, it is equipped with a seven channel Futaba 2.4 system with dual aileron servos hidden in the wing.

RE: SIMLA BUILD THREAD
 

David,

That is my first ARF! I picked it up for $400 at a swap meet in September(I sold two of my airframes for $200 each and turned it into a Top Flite Giant P-40 ARF). I really like to build and finish my models, however, after spending only ten days getting the P-40 ready to fly I have come to appreciate the position ARFs could fill in my hangar.

Bill

RE: SIMLA BUILD THREAD
 

To glass over the old glass, or to just paint the rudder. Whether 'tis nobler in the mind to suffer the slings and arrows of ... Oops. Wrong soliloquy.

Have *finally* finished filling and sanding the rudder so it doesn't have any depressions, etc. While getting the surfaces nice and level, I sanded through the carbon veil in a couple places. Then there's the body filler on top of the veil.

So, the question I have is: Can I paint the rudder as is, or do I need to glass it (again) first?

Thank you,
Richard

RE: SIMLA BUILD THREAD
 

Richard,

I am not familiar with the carbon veil, but if it were me I would probably spray on a couple of coats of urethane clear, followed by 320or 400 sand paper and then paint or primer and then paint depending on how well the clear filled the bare carbon veil spots. I think reglassing would only lend itself to extra and unwanted weight.

Bill

RE: SIMLA BUILD THREAD
 

Bill,

I was thinking along those lines. Shall do it that way. Thank you for the help.

BTW, has anyone heard from Jeff Petroski lately? I asked a question a week or so ago, but haven't heard anything back.

And does anyone know why the instructions have you attach the top fuse blocks before the bottom is at least partially planked? It would *seem* to make more sense to plank the bottom, at least to the half-way point, and then work on the top. For one thing, to do the top, the horizontal and vertical stabs have to be glued in (at least that's what it sounds like). They then would be in the way when planking the bottom.

Cheers,
Richard

RE: SIMLA BUILD THREAD
 

Richard,

body filler is typically a polyurethane based material - it shouldn't be porous. It is also rather hard once dry although sometimes brittle depending on the brand. The glassing of wood is to give it a hard shell and to seal it so that the paint doesn't keep being sucked into the wood grain. If you apply body filler atop a glassed model (very typical) you don't need to reglass the filler. Whether you "glassed" with glass cloth or carbon veil makes little difference.

Once your model is glassed and you've applied filler here and there for a uniform surface, you can proceed to prime. Some will even glass and then apply filler everywhere which is then sanded off to only leave the filler in any remaining exposed grain. I wouldn't add any further "clear" coats - no need for them. I'm sure Bill does and excellent paint job but I believe he is rather unique in using clears such as urethane before using primer. When priming, I recommend you use a thinner sandable sealing primer. Once applied, the primer will show all the blemishes that you thought had taken care of on the model. Use body filler where these are found and then wet sand the sucker down with 400 grit until the model looks like a nasty mess but feels very smooth. Repeat if necessary. Once your surface has one or two coats of sealing primer sanded down, you can apply one or two coats of high build primer, again wet sanded in between. The final coat of primer before paint (whenever you reach that point) wants to have a little tooth so don't sand it down too smooth or the paint won't hold. Depending on the colour scheme (i.e., if you are using white or light colours as a base colour), you might need to top prime with a white primer to provide uniform color tone to the color coats.

If you have a paint gun and want to try a light paint finish, you might want to go with water borne products. Heck, you can even shoot household latex paint with a little care and prior practice. It will look somewhat dull and/or mat once applied but when you apply your final top coat, the colors will really pop if you use a gloss acrylic urethane. If you take a look at Jeff's scratch built Aurora thread, you'll see how he did this with latex water borne paint. Here's the link to where it begins:

http://www.rcuniverse.com/forum/fb.asp?m=7097957

Just some suggestions,

David

RE: SIMLA BUILD THREAD
 

David,

As an experiment I built a modified Taurus and finished it in urethane coatings only. No glass or material of any sort were used. I began with clear urethane over the balsa as a sealer., sanded it with 180 grit dry to a smooth surface, primed it with urethane primer, sanded with 320 grit dry to a paint ready finish. Then I applied the standard base/coat clear/coat Dupont urethane finish. I never had a chance to fly this bird, as I sold it to a gentleman who informed methat it was one of the most rugged models he has ever owned in the 14 years he has been flying R/C. His input was verified by the three landing crashes he put it through and still had a repairable airframe instead of a pile of balsa sticks.http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif

I now have it back for repairs, as I volenteered to repair it for a customer who has since become a friend in the R/C world as well as my instructor for a refresher in R/C flying. You see, it has been over 35 years since I last flew an R/C plane. That is until last weekend when we finally got me some stick time on the old buddy box system. It was great fun and I am anxiously awaiting the time when I become competent enough to solo my Simla!!http://www.rcuniverse.com/forum/js/f...ular_smile.gif

Bill

PS- The reason I suggested that Richard recoat with urethane clear was to fill any raw stranding from the carbon veil. That is if there was any stranding. I also find that when I clear urethane the balsa I can apply fillers over it (after it is scuff sanded with 180 grit) without the need for glass or material covering. And I forgot to mention the modified Taurus was the lightest 60 size plane in my hangar by as much as 2.5 lbs.

Bye Now
Bill

RE: SIMLA BUILD THREAD
 

I can typically do a 10 oz finish with dope and tissue or CF veil, on a four color, 770 sq in model. I'm going to do my Cream Puff that way. It'll be neat to see the difference in weight between the finishes if nothing else, as well as see what the finish weighs on a 9 footer.
Chris...

RE: SIMLA BUILD THREAD
 

HIGH EVERYONE

Seeing that everyone is talking about covering and painting is encouraging...it means you guys are getting closer to the final finish, equipment installation, and finally flying.

I'd like to return to the subject of building the wing just for a moment. I'll find the reference in the thread later, but basically I was saying I set out to weigh the wing balsa, (ribs, spars, and sheeting), and put all the heaviest pieces on the LEFT WING in order to avoid having to add weight to laterally balance. When you have a side-mounted engine, (right side), the left wing usually requires between 1-2 oz to balance that out. By deliberately placing the heaviest pieces on the left wing, you might be able to save those 1-2 ounces. I have now built two wings with this method...the Simla wing, and the new King Altair wing I posted earlier in this thread.

Now for the results...I finally got everything installed and all the linkages made, and "surprise, surprise"....the left wing was too heavy. I had to add almost as much weight to the right wing. The lesson to be learned is NOT TO PUT ALL the heaviest wood on one side, but instead, maybe about 2/3 of it. Both the Simla wing, and especially the Altair wing required weight on the right wing, (the supposedly "heavy side").

The good news overall was that I was able to shave a full 11oz from the previous weight of the King, with the final weight, (with an OS .91 FS in the nose) weighing in at 7lbs 10oz....not bad considering such a large plane, (clipped to 70 inch wingspan, and quite a long tail moment, the King is a large plane...see attached). I flew the Altair once a few days ago...amazing the difference a different wing makes to the flying characteristics...it's going to need to be retrimmed. ;)

I still believe in weighing all the wood and putting MOST of the heavier wood on the left wing...like I said, maybe about 2/3 of it.

Later,
Duane

RE: SIMLA BUILD THREAD
 

Duane,

Just weighed my wing halves yet againhttp://www.rcuniverse.com/forum/js/f...eeth_smile.gif. Rt. wing half came to 28.4 ozs. and Lt. wing half to 29.6 ozs. making the left wing 1.2 ozs. heavier. When I laterally balanced my Simla, it was fully loaded with everything but fuel and required only 1/4 oz. added to the left wing to bring it into balance. The fuselage was in finishprimer and the wing halves were in uncovered balsa. With a little bit of effort I should be able to "paint" in the required 1/4 oz. into the left wing half, eliminating the need to add extra weight. The wings also had all hardware installed including servos, linkages, and landing gear. At this point, I can't help but think that I'm on the right track. What do you think?

Bill

RE: SIMLA BUILD THREAD
 

I'm at work, and I can't remember the wing weights off my head, so I'll weigh the finished wings tonight and report back to you. If those weights are correct, (total of 58oz or over 3-1/2 lbs, plus tube), and they are still bare balsa, that sounds a bit on the heavy side to me, but I need to check again. I think my unfinished wing halves were under two pounds with the contest balsa, but the primer and polyurethane Radio South finish added a lot to the weight, (at least the way I "gooped" it on.

Sounds like the lateral balancing is right on...adding only 1/4 ounce is excellent. "Weight is weight", but maybe weight in the form of extra paint will make it look shiny-er...it will probably look a lot better than adding lead, then fixing the hole. ;)

Duane

RE: SIMLA BUILD THREAD
 

Duane,

I am guessing that when you weigh your wing halves that they are fully finished and loaded with all necessary hardware. I am also thinking that some of the extra weight is attributable to the four carbon fiber rods I used to stiffen the wing. I don,'t think ,however, that they are necessary and I will most likely eliminate them from the next build. I'm also planning to cut lightening holes in the last five ribs(four if I go 96") in the wing and go for a cap stripped material covered wing and tail feathers. Throw in some reduction in the size of spar, leading edge material, and rib material in the tail feathers with contest balsa through out the entire airframe and just maybe I will slim the Simla a bit.http://www.rcuniverse.com/forum/js/f...sn/biggrin.gifOh, and a smaller engine than the 120 AX. Basically all this hinges on the results of a few flights of Simla #4.http://www.rcuniverse.com/forum/js/f...ular_smile.gifThat is #4if I get my rear in gear and get her finished. We are supposed to be off from work next week so it is going to be pedal to the metal to get her painted.

Bill

PS- With the 120 AX I don't really think a little extra weight will be of great significance. However..............http://www.rcuniverse.com/forum/js/f.../msn/50_50.gif

RE: SIMLA BUILD THREAD
 

Great results with the new wing, Duane.
I think that this model with your blue and yellow scheme is one the best looking Classics around.
Chris...

RE: SIMLA BUILD THREAD
 

Duane,

I wasn't so much thinking about adding more weight to the left wing half, but using less on the right wing. Is the glass half full or half empty?http://www.rcuniverse.com/forum/js/f.../msn/72_72.gif

Bill

RE: SIMLA BUILD THREAD
 

Wow, you guys have been moving along! Great thread Duane!

Just a note, released the 2nd production run of Simla's last night (Tuesday, Dec 19 - two days before the end of Fall :D). As of this writing (one day later) a third of them have already been sold. Two heading to Switzerland and two to dear old New Zealand!

Haven't started on the Taurus II yet Duane but I'm gaining on it!

RE: SIMLA BUILD THREAD
 

Yeah, it's probably the CF rods...forgot about them. You know it really doesn't matter that much to save every ounce unless you have a particular engine in mind. That 120 should really make it perform.

Forgot to weigh the wings...yes they are finished.

Duane

RE: SIMLA BUILD THREAD
 

Duane,

Just ordered Simla number two. Here we go again!http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif

Bill

RE: SIMLA BUILD THREAD
 

Duane,

If I can get Simla number 2 anywhere close to 8 pounds I think I'll try a 65AX. From what I've seen lately, it's not going to be the weight so much asthe drag that the size of the Simla creates that could be my biggest hurdle. I guess only time will tell. I should think that if ED could make her fly with 60's of the day we should be able to achieve similar results with the engines and smaller and lighter radios of today. What do ya think?http://www.rcuniverse.com/forum/js/f...ngel_smile.gif

Bill

RE: SIMLA BUILD THREAD
 

Bill,
I, for one, will be very interested to see how you come out on this. I think it can be done, let me know if I can help.

RE: SIMLA BUILD THREAD
 

Jeff,

I am curious as to how far you would go to make the Simla as light as possible. What liberties would you take to get it competitive with a 60 or 65 engine; cap strip construction as opposed to full sheeting, reduced size of structual components, etc., etc.? And of course keep it's overall dimensions and shape intact.

I was doing a little math on eliminating some of the components that I used on my first Simla. Using one battery pack instead of two -5.4 ozs, 65 AX instead of 120 AX -5.2 ozs., eliminating the carbon fiber rods I used as stiffeners - 2.0 ozs., clipped wings and lighter contruction techniques - unknown quantity of ozs., no steering linkage, lighter control rods, and the list goes on and on.

The big one for me is the finishing method to use. Film covering or paint?The film would be lighter, but I believe the paint job just looks better as well as more professional. And the fact of the matter is I have only done one film job and virtually an infinite number of paint jobs. That is why I am working so hard to get my painting technique as light as possible on my first Simla.

Anyway, thanks to your quick response I should have Simla number two on Friday. and as I stated earlier "the fun will begin."(Again)

Bill

RE: SIMLA BUILD THREAD
 

Bil;

I have absolutely no doubt you could save all the weight you mentioned in a modified Simla, but of course that wasn't our goal with the Simla project. If Ed sheeted the wing, we wanted to sheet the wings as well. Actually I'm a little surprised that Ed didn't want to use open wing areas with capstrips instead of fully sheeting the wings. He knew it was a large model, and he had large open areas on the Taurus.

Kevin Clark and I were talking earlier on about building what we called "an updated Simla", (kind of what we figure Ed would do now) as a future project. We want to do a lot of the same things you mentioned, (ie clipped wings (to make it 2-meter), redesigned fuselage with more side area, and in our case, a LARGER engine, [than the 2-stroke .90) for vertical performance that approximates the more modern 2-meter jobs).

I weighed the wing halves of the kit prototype:

Left wing: 1lb 12.3oz
Right wing: 1lb 15.3oz
C.F. tube: 2.3oz

Total: 3lbs 11oz....and this is of course ready to fly with landing gear, wheels etc., so your wing pre-finishing weighs about the same as mine RTF.

Duane

RE: SIMLA BUILD THREAD
 

Duane, Ed might have been concerned about twisting of the swept wing. Besides, there was obviously very light balsa available so there was no real problem sheeting the whole wing. The "carrier wing" has diagonal braces to stiffen it against torsion, that's why I think that might be the reason.

And as to the AUW, didn't Kevin Clark do a lightweight job with his Simla?

RE: SIMLA BUILD THREAD
 

Bill,
A few quick ideas which you probably have already considered. But, it's good to "air them out".

Like Burkard I would be weary of removing all of the sheeting. There is quite a bit of weight in that sheeting though. Eight pieces of 3/32 x 6 x 48 can get heavy, how much would you save with contest? I think I would adopt the Taurus type of covering. Glue in a sheet on the leading and trailing edges with cap strips on the ribs and consider shear webs. Reduce the span to 96".

Hollow out the top blocks even more or go with Cees's method and remove them. Hollow out the wing tips, stab tips. Cut lightening holes into the 1/8 fuse sides and take a bit more out of the fuse ply doubler. Though I have already laser cut quite a bit out of it and the wing ribs.

I wouldn't open up the 3/32 balsa fuse especially aft of the wing. There is a lot of moment there and plenty of force generated from that huge stab, could crack the the fuse if not trussed correctly. Anything forward of the firewall (cowl and such) is for looks. Obviously, no structural worth at all. Remove whatever you can there or thin it out. Finally, ribs one thru five are all ply or ply/balsa laminates. More than anything else just there to provide a safe, structural surrounding for the tube. Could experiment with reducing the weight with those 10 rib locations. Although, as I mentioned above, I have already cut lightening holes into them.

Hope this helps a little bit anyway. I'll study it a bit more.

RE: SIMLA BUILD THREAD
 

Duane,

I have not forgotten the parameters of the first build. That is one of the reasons I am going to finish my first Simla in Ed's colors. However, in the interest ofaffirmative progress, a few liberties on a second build not only seem to be okay, but almost in demand. I admit to being one of those people who is always in search of a better "mouse trap".http://www.rcuniverse.com/forum/js/f...sn/biggrin.gifAfter all, if we had not made a few improvemnets on the Wright Brothers original design where would the F-22 Raptor be?http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif The bottom line for me at least is this forum, the build, the people, the Simla, future prospects, and so forth all add to the great good fun of being a part of the R/C community!!!!!!!!!!!!!!!!

BTW- Has there been any more discussion on the "Simla Fly In"( for lack of a better name)? I have really begun to look forward to such a gathering. More great good fun!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Bill