RE: SIMLA BUILD THREAD
 

Duane,

I've been following the Simla builds with interest. In reading your comment above about the wing tips, I thought I would post a couple of comments on the subject:

The nice aspect of producing modern kits is that with a laser or CNC cutter, one can produce specific "planform" shapes to exactness. What I mean by this is that if a wing tip has a specific design when viewed from above, then, one way to obtain wing tips which have a consistent planform appearance is to cut them exactly to plan. If one cuts tips which are roughed in rather than to design, then, while it isn't an issue from a flight standpoint (at least not significantly), each wing will likely be "personalized" and have a slightly different look based on these details. Of course, if the tips are cut to planform with no other aid, then one runs into the issue that uniformity will likely be lost as well because one builder might sand more aggressively than another.

Getting to the point, one method which I have come to like in order to preserve the planform and constant shape of the tip is to build the tips with "spliced keels". This has been done for a long time especially by the Japanese and basically consists of splitting the tip in half chord wise (or cutting two thinner tips which will be laminated) and inserting a hard keel in between. 1/32" ply or plastic works well for this as it provides a "guide" when sanding and prevents one from over sanding and loosing the planform design in the process. It also aids in solving the problem of "paper thin" TE's where the tip is sanded to the thickness of the aileron TE. The inset ply as well as the glue used to laminate the top and bottom tips to the keel produced a rather hard TE area and, when sanding, one discovers that it is difficult to sand the balsa right down to the ply unless sanded very vigorously. As a result, the tip TE ends up being about 1/16" thick (accounting for the ply keel plus 1/32" of balsa above and below it) which is not a bad thickness for the TE of a pattern wing - tip and aileron. Finally, the design of the keel can aid as a guide in the hollowing out process as it can delimit the extent to which the tip is lightened.

A reduced scale (25 size) UFO that I re-designed in CAD was designed in this way. Ralph is building the first prototype in an active thread on the forum and the tip structure and elevator TE can be seen in his last couple of posts on the thread. I now build all my tips in this fashion and they result in a very strong dent free area.

Perhaps you have known and/or seen this approach many times before and my post might be unnecessary. Then again, perhaps this approach goes against the classic original design of the Simla and for that reason wasn't used.

David.

RE: SIMLA BUILD THREAD
 

David,

I don't wish to seem to be splitting hairs, but 1/32" for the ply keel plus 1/32" upper and lower wing tip sections gives a TE of 3/32", not 1/16". At any rate,it does sound like an effective way to solve the deminishing wing tip trailing edgeproblem. I'll have to try it and see. Thanks for the heads up!

Bill

RE: SIMLA BUILD THREAD
 

Well, bother! [:o]

I apparently became confused between left and right. Not the first time. A Marine drill instructor once told me "Your *other* right foot!"

Looks like it's time to order another kit (or just the fuse parts if possible). I can work on the wing in the meantime.

Richard

RE: SIMLA BUILD THREAD
 

As I said, I don't know if Jeff addressed the "tip problem"...I just wanted to point it out. You MIGHT want to make them another 1/8" larger to account for the "disappearance" of the tips in the lower corner. At any rate, try to get the tips to look like the picture above, and you'll be OK.

As for rg1911's problem with the fuselage sides, I can't remember if the balsa sides themselves are different, but the ply doublers certainly are. When placed on the correct fuselage side, they are primarily responsible for making sure F1 has the proper amount of DOWNTHRUST and RIGHT THRUST. As billberry said, you can test this by checking to see that the right side, (from above), of the F-1 former is behind the left side, (F-1 is slanted to the right), and at the same time is slanted DOWNWARDS. Hopefully that's the case, but if your model is reversed, you have a thrust problem. If the doublers, (and the thrust), is correct, then there has to be some other explanation. Are the front and back of the wing saddle openings on each side directly across from each other by using a square?

If the formers were reversed, the fix could be messy, or even next to impossible, since those formers should be anchored in there with epoxy. The important thing is you need to provide both RIGHT and DOWN thrust somehow...perhaps through spacers of some sort to counteract what was built in. The wing saddle must be perpendicular.

Let us know...and hope it's something minor that's causing your problem.

Duane

RE: SIMLA BUILD THREAD
 

Richard,

Hold on there brother! Don't order another kit just yet. If my calculations are correct, you should have enough left over wing sheetingto create the necessary fuselage side to fix your problem. I say that because you have already indicated that you ordered contest balsa for wing sheeting. I'm not trying to deny Jeff any sales, I'm just trying to help you with a problem that has happened to many of us over the years. I suspect that you could reproduce the parts needed for way less than the new kit price. I'm guessing in the $5 to $10 range. Save that money for a second kit, for a second build. It's too bad you live so far away. If you were here I could probably have you back on track in half anhour or so.

I am inclosing some photos of my rudimentary fuselage jig. I place the plans over a 48" longbuild board and clamp two aluminum angles down the sides of the fuselage plan. Then I place the fuselage sides upside down inside the jig and over the plans. Atthis point I have alreadyinstalled all triangle stiffeners, longerons, etc to the fuse sides. ThenallI have to do is glue thesecond and third former in place, making sure that they are perpendicular to the fuse sides and the build board.Assuming that I have doneeveything correctly and after formers 2 and 3 have set up, I glue the firewall formerin place, aligning it with theplywood fuselagedoublers. I usually leave the whole assembly in thejig until I have glued the aft fuselage together over the plans so that I get a straight and truecenter line down the fuselage.

Bill

PS- You'll probably notice that I used the Taurus pieces as an example since my Simla fuselage is already completed.

RE: SIMLA BUILD THREAD
 

I checked the Great Planes site and the Power Plane is listed as Discontinued, and I couldn't find one listed on Amazon or eBay. I'm sure *some* hobby shop still has one gathering dust, but finding that one shop would be a bear.

I'll check with my local shop when he opens in another hour.

Bill: I do have a Power Plane (and actually found it yesterday). I'll be happy to let you borrow it, since it doesn't look like I'll need it immediately.

Cheers,
Richard

RE: SIMLA BUILD THREAD
 

Yes, sounds like a great idea...the problem in my case was that it's something you have to do "in advance" to ensure the correct shape, and something well worth doing. When I built the prototype, I didn't realize, (neither did Kevin), that this would happen. You know, I guess this kind of thing is more likely to happen with unconventionally shaped tips such as the Simla, and not with the regularly rounded tip.

Thanks for the complement on the build thread...this is the first I've done...and the first I've followed from front to back. We are trying to make it interesting and informative...interesting like the Simla.:)

Duane

RE: SIMLA BUILD THREAD
 

Duane,

Never would haveguessed that this was your first buildthread. The Simla seems to have brought a bunch of usfirst timers together.http://www.rcuniverse.com/forum/js/f...ular_smile.gifIt never ceases to amaze methat thelegacy of someone as talented as Ed Kazmirski can and does affect so many people as time goes on andin so many ways.

Bill

RE: SIMLA BUILD THREAD
 

And you're doing a bang-up job, Duane. Many thanks to you and Bill for keeping me going.

Cheers,
Richard

RE: SIMLA BUILD THREAD
 

Bill,

I'll take a closer look at the mess tonight after work. Perhaps some more measurements will give me a clue as to where I pooched the doublers. (I had thought I was so careful.) Jeff did write that he *might* have some fuse parts kicking around.

If he doesn't, I'll use your suggestions and see what can be done to salvage the situation.

Next time, I'll label both sides of the fuse pieces with both left and right, and top and bottom. Hind-sight being 20/20, I should have thought to do that originally.

I checked my local hobby shop and confirmed that the Power Plane has been discontinued and that Dan doesn't have any left. So you're more than welcome to borrow mine.

Cheers,
Richard

RE: SIMLA BUILD THREAD
 

Richard,

Thanks for the offer, but I have already finished hand sanding the leading and trailing edges. Maybe the next time.

As I remember the fusleage sides and the plywood doublers were stampedwith right and left markers. Also, I wouldn't worry about the nose block placement until after the formers are glued in, After that they pretty much just fall into place. I would guesstimate that I removed 85% to 90% of the material in the nose blocks anyway.

Bill

RE: SIMLA BUILD THREAD
 

The whole Simla project is something that has been fascinating to me since (July)?? 2007, (actually before), when the little picture of it was included in my second article for Model Aviation, and that little picture "stole the show". I definitely remember seeing that back cover when I was a 14 year old kid, and thinking how COOL that plane was...YES, you can use the word "COOL" when referring to R/C vintage pattern. Everybody I've ever shown the picture of the Simla to has loved it, including Michael Ransey from Model Aviation.

This is a plane with a history and a story behind it. Jeff and I have been immersed in the project for a very long time in one way or another from research to finished kit, and we probably know as much as can be known about this design...(with the possible exception of Cees), and we are constantly hoping other "eye witnesses" and photos will come forward and add to the "information pool." I'd like to share information with Cees...the object being to get the best Simla possible.

This has been the most fascinating project I've worked on, and as much as possible, I want to give readers of this build thread the "inside story" on Ed, and the development of the Simla plan and kit.

BTW...I've been looking at the number of "hits" vs the number of responses, and pages compared to other threads here on RCU. It looks to me like we don't have as many DIFFERENT PEOPLE, (we have a smaller audience, and not as many people who "audit" the thread...there is a term for that, but I can't remember it), than some threads, but we have a LOYAL audience, and a group that likes to interact and help each other. I'm going to suggest to Jeff that he recommend the thread to everyone who buys a kit, so hopefully new ideas and questions will come up over time...afterall, we have 50 Simlas about to be built!! :D:D

Duane

RE: SIMLA BUILD THREAD
 

Bill,

thanks for the correction - 3 x 1/32 is indeed 3/32". Actually, I like to use 3/32" square HW along the TE of control surfaces to prevent dings and aid in the trueness of the surface once sanded and finished. In the end, once the tip and ailerons/elevators are sanded down to contour one ends up with a width of somewhere between 1/32" and 3/32" with 1/16" being a typical thickness. I find 1/32" to be a tad thin and weak but with very wide small percentage airfoils one can end up with a very sharp TE. The Pylon guys of course bring them down to 1/64" - razor sharp edges which they typically obtain by splicing obeechi ply in between their wing sheeting along the TE of the wing/stab.

For the UFO I actually cut the keels from 1/16" ply which is almost excessively strong but the idea was that if the tip balsa was sanded right down to the keel, one would have the desired TE thickness. Wood glue of course helps when laminating the tips to ensure the TE remain nicely sandable.

Another detail I discovered is that when there is some roundness or curvature to the TE of the tip, then the keel wrapping all the way back to the aileron is effective. On the other hand, when the tip has a straight TE which essentially continues the aileron, then it is preferable to omit the keel in the TE of the tip and use the same square HW that is used on the ailerons. Using the HW is actually a very effective way to insure proper attachment of the tips along their centerlines and produce symmetric tips about the wing. It also aids in centering the ailerons from root to tip.

In any case, I think the idea is clear. 1/32" ply "hooks" as keels are a good all around compromise between strength and weight and preserve the planform nicely. The snaps show the use of a plastic 1/32" thick keel in a tip. It's a little hard to see but one can appreciate that the TE of the tip didn't "feather out" due to the curvature and thinness of the tip in that area. This particular model was kit built so I decided not to add the HW along the TE of the controls which were pre-sanded to shape.

David.

RE: SIMLA BUILD THREAD
 

Duane,

I would typically be part of the "audience" sector of the thread followers but somehow found myself making a couple of posts. These models are way before my time so my interest has been seeded by following these threads and seeing the models being built and flown.

I have to confess that personally I find the Simla is a fine looking craft compared to Ed's more successful Taurus.

David.

RE: SIMLA BUILD THREAD
 

In short what you are saying is the Simla is NEW...to you, and that's the great thing about it. There is no law that says you can only be interested in something if you personally remember and flew it from "yesteryear". If it LOOKS COOL, it FLIES WELL, and it IS DIFFERENT FROM EVERYTHING ELSE AT THE FIELD......then BUILD ONE. [8D]

That is also what I like about SPA. You don't have to have flown the planes to enjoy competing with vintage, simple and inexpensive models. These "vintage" planes are NEW to most everyone under 40, and we have some former pattern pilots that have a new-found appreciation for competing in vintage pattern, who didn't personally know the models when they competed. Competition in front of judges with your plane is not an AGE thing.

Duane

RE: SIMLA BUILD THREAD
 

A quick note about .3-ounce carbon veil as a covering material.

This may be one of my ideas that doesn't work well except on flat surfaces. I covered the rudder yesterday and quickly learned that the veil does not want to follow curves, such as the rounded trailing edge. It also tears more easily than expected.

I've thought of a couple possible fixes, but they would waste a lot of expensive veil. (Of course, if I can't use it, I'll definitely waste a lot of expensive veil.)

If I don't find out what the trick is, I'll go back to glass cloth.

Cheers(?),
Richard

RE: SIMLA BUILD THREAD
 

Duane,

I think you might have misread my post. The Simla is not new to me in terms of being aware of it - I just never saw one in the flesh. I'm sure there are many great things about the Simla but it just isn't part of my classic upbringing. I learned to fly RC in the early 80's but am not under 40. Also, by enlarge, just about any classic pattern model one brings to the field - at least up here - is different. As we know, we live in a sea of ARF's.

SPA is not on my radar. I don't live in the US currently but also don't have an interest in competing at present. Maybe when my kids are a little older.

David.

RE: SIMLA BUILD THREAD
 

In short what you are saying is the Simla is NEW...to you, and that's the great thing about it. There is no law that says you can only be interested in something if you personally remember and flew it from "yesteryear". If it LOOKS COOL, it FLIES WELL, and it IS DIFFERENT FROM EVERYTHING ELSE AT THE FIELD......then BUILD ONE. [8D]


Duane
[/quote]

Duane,

That describes me to a "T". Back in the day(1975) I was aware of Ed and his accomplishments, and I flew several Taurus' in one form or another. But I was totally unaware of the Simla's existence until one day I saw the "Ed Kazmirski's Taurus" thread on RCU where you posted of it's existence. The rest is history as they say, since the moment I laid eyes on the Simla it was love at first sight. As I stated in an earlier post, it can get pretty boring when one is retired with 24/7 filled with nothing to do. This experience, however, offers methe oppotunity to be involved in a great project and hopefully become friends with some very well informed, funny, and likeable characters. And then there is the possibility of the "Simla Spectacular" get together. Though it won't be easy for me to make it, it's the one thing I look forward tothe most.http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif

Bill

RE: SIMLA BUILD THREAD
 

Just a note on " those tips". I just finished shaping the left wing tip. It started as a 3.4 oz. block and finished as a less than 0.5 oz. wing tip. I was sort of counting on the tip weight to help with the lateral balance, but it looks likethat isgoing to be anon issue unless the 2.6 oz. right tip block comes in at -0.3 oz. And that's a trick I don't think I can pull off. Maybe helium in the right tip after I carve it out.http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif

RE: SIMLA BUILD THREAD
 

Apropos of nothing, I just remembered that the town of Simla, Colorado, is just an hour or so down the road.

Cheers,
Richard

RE: SIMLA BUILD THREAD
 

Hmmmmmmmmmmmmmmm," Simla Spectacular" in Simla, Colorado. Nice try, Richard!http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif

RE: SIMLA BUILD THREAD
 

Curses, foiled again! :D

More and more it's looking like I need to go back to glass cloth. I'm getting *lots* of replies to the effect that the veil requires large amounts of resin/urethane (and it doesn't drape well). This may be a case where it's perfect for some applications, but not all.

So, what are people's recommendations for the weight and source for the cloth? I've seen a couple posts elsewhere that suggest using the 3/4-ounce cloth because it has a tighter weave requiring less resin/urethane than the 1/2-ounce cloth. Thoughts?

Cheers,
Richard

RE: SIMLA BUILD THREAD
 

Richard,

are you putting the carbon veil underneath the sheeting or above it as a finishing system? You should talk to Matt (MTK). He uses the stuff all the time and is quite familiar with it. Mind you, he's using it mostly for 2m pattern ships.

David.

RE: SIMLA BUILD THREAD
 

David,

Thank you for the suggestion. I've sent MTK a PM.

I'm using the veil as the finishing system.

Richard

RE: SIMLA BUILD THREAD
 

For a very nominal amount, Jeff is sending me a set of fuse parts that he had culled (for cosmetic reasons) from the last kit run. This time I'm going to steal Bill's jig idea and test fit *everything* before adding glue.

In the meantime, I'll start on the wings.

Any thoughts on .5-ounce versus .75-ounce glass will be appreciated.

Cheers,
Richard