2002 Stunter

I have just finished drawing a set of building plans for a new Magnum MKII (or Magnum Pro) and hope to be able to start construction after the team trials. It will feature molded fuselage blocks and a simplified I-Beam wing type of construction. The stabilizer, elevator, fin, and rudder are also built up to keep the weight to a minimum.

Its looks somewhat resemble the original I-Beam Magnums that I built in the 70’s, only it has a deeper fuselage and longer tail moment. By using carbon fiber materials and other composites I have been able to reduce the amount of wood in the model while greatly increasing the strength. Of course all of the modern control system components will be used, i.e. 4” bellcrank, 1/8” HD flap horn, adjustable elevator horn, adjustable tip weight box, adjustable lead out guide, and C/F pushrods. The model has 700 square inches of wing area (perfect) with a fairly thick airfoil set at 22% at the root, and 24% at the tip. Projected weight should be around 52 to 54 ounces. Power will be my old reliable PA .61 and pipe set up that I become so fond of. This set up has worked just great from the beginning and I would not consider changing. Besides I have a small fortune invested in props.

I have had my fill of the super trick paints so I am returning to the tried and true dope and silkspan finishes that I have use in the past. It is still my opinion that there is nothing that has as deep a shine as a rubbed out dope finish.

Well that’s my new project, now how about yours.

I spent last winter building a (slightly modified) version of your Skyray (I used 1/8" balsa ribs, and made the fues a bit longer in an effort to get the CG to come out right), and I've since built a Flite Streak - both from plans. I should mention I'm a beginner - these were my first two stunters, both powered by McCoy 35's.

For next year, I have a Brodak Smoothie kit, and a 40th Anniversary Fox 35 (NIB) to power it. Since the Smoothie is a 1951 design, and the Flite Streak was designed in 1956 (the year I was born), I'm not exactly on the cutting edge. No matter, I'm learning a lot, and having a blast! I should mention that my Skyray version survived a number of "unintended landings" mostly intact, until yesterday when I stove it in rightly (outboard wing broke off). I think I'll still be able to repair it, though. That was one great design as a stunt trainer!

Al Rabe used to put the smallest wing on that would deliver the amount of lift he felt he needed. And he wasn't afraid to chop some off if he felt it was too big. Bob Hunt has made the observation that a 550 to 600 square inch plane would handle the wind better than a larger one. (I also don't know how he determined that.)

Matt is currently working on a new Stuka very similar to the present version (different paint job and slight other variations). He will reduce the amount of flap area on this ship, however, as several times now he has had to increase the amount of elevator throw in proportion to the flap. And his isn't nearly as light as you project for yours. His is 690 square inches, by the way, and the reduced flap area on the new one will trim a bit of that (although he may just shorten the amount of moveable flap).

But, the fact that he has had to reduce (in effect) the amount of flap throw in proportion to elevator throw has led me to wonder if, instead of trimming flap area, one could trim wing area and achieve the same result. The wing is built, however, so that won't be done on this plane, and it will just leave me wondering for a while.

So, being curious, why do you feel 700 square inches is "perfect"?

Many other factors come into play here like airfoil thickness and available power (not much of a problem with today’s engines). Some models were designed to take full advantage of a particular engine. A good example would be the ST.60. Many models were designed with large wing areas and thick airfoils to harness the power of this engine. My box label Magnum was powered by a ST .60 that was de-tuned to keep the model from running away (small venturi, extra head gaskets, and 12-1/2” three bladed prop, 5% Nitro and so on.). When this model was new it only weighed 59 ounces and had a wing loading of 12.1. It flew pretty good but I always thought it could have used a thicker airfoil to help hold the ST.60 back.

Is 700 square inches the perfect wing area? It is in my opinion when you use the airfoil percentages and total flying weights that I do. Paul Walker and I had this discussion years ago when I first finished the Magnum Force. He asked what the wing area was on my new model, 715 square inches I proudly answered. Paul’s reply was Hmmmm! That’s 15 square inches from perfect.

Thanks, Mike: One thing that you are well aware of and that you are taking into consideration when you come to your above conclusions is that you have a certain weight going in that cannot be changed: Engine, pipe or muffler, tank, fuel, prop, spinner, motor mounts, belcrank, leadouts, pushrod, horns, wheels and gear, tip weight (approximate). Whether you build the plane at 700 square inches or 350, these weights are still going to be there.

However, with the extreme power and thrust that we are now able to achieve with today's planes (Matt is currently turning a 14 inch three-bladed prop on his) weight may not be quite as critical as with the anemic power plants of yesteryear. Some of the 4-stroke guys are coming up with some pretty hefty weights and doing quite well.

Still, it ought to be interesting to see how you come out. I am still a believer, as you point out, that lighter is better. And you set some lofty (or should I say light-weight) goals for your 700 square inch plane.

Leonard Neumann

One thing I forgot about was your altitude (well, not your altitude. The altitude where you fly at.) Lighter weight and more area will be more beneficial to you there than for those of us who fly down here where we can all breath a bit better (and our motors, too).

I am currently scratch building another Oriental which will be 35S powered with shaft extension, also have a nice ST 60 sitting around and want to build something for it, maybe a Shark 45 with foam wing, maybe a Brodak Legacy as I have the kit but always wanted to do a Shark. Will also build up another All American Senior with either Stuka Stunt .25FP or Fox 35 hemi power. A friend is cutting out three 56" span Skylark fuselages,doublers, formers, tail feathers, etc. and am going to do one of these with a foam wing also during the winter months with an Enya 45.Last but not least, am designing a modern type stunter using Brodak Cardinal wing, moments, etc.(not really designing, I guess), full fuse, but with a totally different look using Stuka FP 35 for power. Definitely a full schedule but Ultracoat and Lusterktoe speed things up a lot. This is in addition to the usual assortment of Flite Streaks,design as you go speed limit and vintage fast combat ships, Nemesis II's, etc. that I get an occasional urge to build plus want to add to my Brodak warbird collection-have the Zero and Me 109, next up is the P51B. I really enjoy building, semi scale painting, and flying the warbirds-no kote allowed here. By the way, both warbirds to date are truly outstanding flyers with OS 35S.

Flying at 5000 feet presents a few problems (no air) but they can easily be taken care of. The biggest things that I have run into while flying at this altitude is to make sure you up the Nitro and increase the pitch in props you use.

See ya!
Mike

I just restarted sport C/L and took my kids to the Nats. We saw the walker and 1/2A and now they want to fly contests so I joined AMA. I have to build a something for myself and with them.

The boys and I will be scratch building a pair of Skyrays 35's with FOX 25 baffle piston engines for them. That is a good combination (and I have 2 motors so no fights). I may try fox 19 if they are light enough. These will be for a 7 and 9 year old to learn the beginner pattern. I will shorten the nose a little and they may want the tip shape and tail surface changed. I will probally build another one for myself at the same time. Hey what's one more set of ribs on the band saw. Any comments Mike P?

I will be building something based on a Banshee. It will get the same treatment as a twister. Bigger tail surfaces, shorter nose. A little more span. better flap hardware, 4 inch bell crank ect. It will have either a Fox 40 big case or a stock FP40. The I am tempted to just throw together all the kit wood into one banshee and scratch build something else. I am most just using the moments and the kit engineering. Would like to put a contest grade finish on this one.

Sophomore .19 for OTS powered by a never run .19 red head.

A BiSlob, becasue saw one fly at the nats and laughed my butt off. Fox 35stunt.

For fall winter, thinking of a bigger profile--Cardinal perhaps, for a LA 46. Probably from the kit.

Will finish the "Doctor" from scratch. And would like to do a full fuse ship for later in the year--maybe an Oriental, but I'de really like to try a lost foam geodetic wing like the GEO XL.

So many planes...so little time!

I'm in the middle of working a new one up right now. It's a marriage between the profile Pathfider and the profile Cardinal. I'm designing it for a Saito 45 and am considering using a throttle with it. I'm only sure of one thing as far as the throttle goes. It won't be using a third line.

I like the PF look with trike gear. There are some things I like about the Cardinal airfoil, hence the gene splicing.

If it all works out, I'll do a full house PA ship, blown up a few percenatge points for a Saito .72. Even in the full bodied version I intend to keep the engine side mounted. Cowled in with those nose stiffening "Apple Cheek" cowls ala Shoestring styling.

I need to build another classic ship, and it'll be one of three planes. I'm drawing up the plans for a Hungarian design, Vum 18, that my buddy Gordan Delaney used to fly. Pete Peterson, another of my flying partners just finished his using the wing and rib layout I drew up and it flies great. Pete seems to feel that he may fly his in PAMPA classes as well. I'm waiting to spend some time with Pete, a master builder BTW, and get his input regarding internal structure changes to make the plane build up lighter.

The second plane I'm considering is Sheek's twin boomer, the Torino. I really like it's looks. I understand that Sheek's buddy Vornholtz (sp) almost won the Nat's with the original, until he lost appearance points. Aparently, he forgot to tell anyone that Jack built most of it. But that just tells me that it's a good flying design.

Lastly, I still miss my ##### Williams Electra, the best plane I've had to date. I believe in any case, I'll be building another in the future. I'll probably use RSM's kit after he goes to laser cutting for this one though.

Now, if I can get moved soon and get the shop set up.....and some spare time....

Think of the common nickname for a fella named Richard.

:-D

So, in the future, if you have a person named Richard and want to call him by his common nickname, it will print as you intended.

Do NOT abuse the privilege!

Hmm, good question. Part of it depends on how the plane I'm just finishing flies. It's about 3/4 my own design and the rest from some very gracious contributors. If it flies great, I may build another with a few "improvements". But most likely I'm going to finish my semi-scale version of the Rare Bear. I started this plane about 2 years ago and stopped when I ran into a problem I couldn't figure out. Now that I have had an epiphany (figured a way around the problem), I plan to finish it. Should be cool, if a bit wide bodied. It's really quite scale. I also plan to build a classic plane, but have no idea what it will be right now. Depends on what kind of mood I get in.