Viper 20 years in the making

[RC Storick]

Viper one was built in late 89 and number two was built and flown early 1990. It met its demise by Ron Tool. He had unfortunately hooked the lines up in reverse. Viper two is the precursor to the Vipers I am flying now. Number one was built as a experiment to the weight game. Which was a successful experiment. Number one was 670 Squares and forty ounces. I didn't really like that plane (I still own it) as it was X Kote covered. But it was for experiment only. It was powered by a FP.40.



Number two came into being as a way to step up to the plate with a full blown PAMPA stunter. It was powered by a ST.51 and flown with much success but it still was not what I was looking for. Along the way I built many other airplanes of other peoples designs, still didn't do it for me. I guess I was chasing my tail in search of the planes of my youth. The Viper Super Glide was built and was 50 oz but it still lacked something (POWER) It was powered by a FP.40 on a pipe. I had flown that for a season and sold it to a John L from Fox. along with it went the sorcerer which was powered by a OS.32F on a pipe (more power experimenting).

One test is worth a thousand theory's. the Viper I am flying now is by far the best of both worlds. It light (all tho next one will be lighter) and well powered. I guess I could add some dirties to make it like what I have been flying. Will I do well at the NATS? Well it wont be because I don't have a great flying plane. I think the coarse is set for the next plane. I had been planing to take it up a inch in span but I am not sure I will go that route. It seems to add a scaling effect. More span more weight.



The latest Viper is powered by a PA.65 and weighs after trim 53.5 oz. Wing loading on this plane is 11.852 oz per square foot and I am more than happy with the final results of all the work. At this point I just wish I had built 2 of them. This plane was built around the .40 size engine as I want to fly with .015 lines. After the rule change it was changed over to the big block.

I think the hardest thing for me to get out of my mind this year was its a flying event not a finishing contest (and I am still working on this) as the finish on this plane is sparse. However it should look good from a hundred feet away flying.

[Randy Powell]

Robert,

I believe you are on a good track. Weight is important. Even when the wing will carry the weight, there are inertial effects you have to get around with a heavier plane. I agree, it's become a flying event with shine running a distant second. But I still have to look at it so I do the best finish I can commensurate with reasonable weight.

[RC Storick]

Robert,

I believe you are on a good track. Weight is important. Even when the wing will carry the weight, there are inertial effects you have to get around with a heavier plane. I agree, it's become a flying event with shine running a distant second. But I still have to look at it so I do the best finish I can commensurate with reasonable weight.

What attracted me to this HOBBY was going to Whitter Narrows and seeing all the beautiful planes. I think if I had seen 50 Nobler ARFS I would have flown RC pylon. Back in that day the pylon racers were beautiful planes made from glass and wood not like now a days made from foam board and duct tape.

[Randy Powell]

Robert,

I agree. It's what attracted me in the first place. From semi-scales and units modeled on civilian craft and racers to star ships and flights of fancy (pun intended), I love stunt planes. Beautiful planes flying a pattern is what hooked me. And here I am, 40 years later still hooked.

[Howard Rush]

That's what attracted me, too.

[proparc]

Seeing all the killer stunt ships from Bill Simons, Gene Schaeffer, Bob Lampione, Bob Hunt, Big Jim Greenaway-the mind boggling ships from Vic Macaluso,( I don't think I will ever fully recover form those) and all the other East Coast greats really did it for me. And then to turn around and see those same great ships in Flying Models magazine was just about more than I could take!!!

[Wynn Robins]

with my painting skills (or lack thereof) your viper 8 looks good to me!!!!!!

looking forward to seeing the next in the line of this breed - and to find out how it goes for you.......i am a believer on the weight issue - as you know! 

[Matt Colan]

Sparky, any stories about Viper 3, 4, 5, 6, and 7?

Designing a new ship from the ground up seems to take a few years of modifications before it gets right.  I really like CL better than RC, more raw beauty in this event rather than ARFs.

[Crist Rigotti]

Looks like Sparky figures his wing loading down to the one thousandth of an ounce per square foot.  Wow, what precision!   

[RC Storick]

Looks like Sparky figures his wing loading down to the one thousandth of an ounce per square foot.  Wow, what precision!  

  Well its really 11.85230769207692307692307692308 per square foot. Thats as close as I can see it..  

Wishing it was 10

[RC Storick]

Sparky, any stories about Viper 3, 4, 5, 6, and 7?

Designing a new ship from the ground up seems to take a few years of modifications before it gets right.  I really like CL better than RC, more raw beauty in this event rather than ARFs.

Viper 6 was a dud its hanging on the wall here. Nice looking but it has some problems. Too heavy, When I did the wing I made it a 1/8th of a inch too thin and the bell crank is in the wrong location. So its on the wall as a remembrance to pay attention.



Seven was sold before flying it. Pictures are here somewhere. Pictures of number one is somewhere here also the forum is getting so big I can't find it right off.

[Doug Moon]

How do you measure your square inches?

[RC Storick]

By panels not by averages.

[Randy Powell]

Fancher had a great formula for calculating wing area. had to do with measuring all the way around the wing - total distance - then dividing by, hmm, average chord? Don't remember, but I have it written down somewhere.

[RC Storick]

Fancher had a great formula for calculating wing area. had to do with measuring all the way around the wing - total distance - then dividing by, hmm, average chord? Don't remember, but I have it written down somewhere.

Measure across the wing (less tips) multiply by tip cord. Subtract tip cord from root cord times that number by half span = total wing area less flaps and tips. Do the same for flaps. Because tips are rounded you can figure it close the same way doubled. Add them all together and wallah total area..

Come on Brett I know that you know a better way?

[Randy Ryan]

Here's another way to figure area. Use poster board. Cut out a piece say 6"x6", that's 36 sq inches. Weight it and divide by 36, that's weight/sq in. Layout the wing panel on posterboard and cut it out. Cut into manageable pieces and weigh it and divid e that by your Sq In weight. This is very accurate if your careful with the layout, paper product weights are very carefully controlled. This is really helpful on eliptical and odd shaded surfaces. This method was used for years in Free Flight where every model had to be processed, it left no doubt and it was fast.

Sparky, really nice looking model, look forward to hearing more on its flying capabilities.

[Brett Buck]

Measure across the wing (less tips) multiply by tip cord. Subtract tip cord from root cord times that number by half span = total wing area less flaps and tips. Do the same for flaps. Because tips are rounded you can figure it close the same way doubled. Add them all together and wallah total area..

Come on Brett I know that you know a better way?

    I do it the same way you do!   I know a bunch of other ways but not any better ways. This method is adequately accurate and admirably quick.

     Brett

[Ted Fancher]

A great series of airplanes, Sparky.  Just because it's sort of "my" thing I'd be interested in the aerodynamic progression of the series; i.e. what you changed and why from version to version?  Which things worked and which didn't for you?

Ted

[Matt Colan]

Seven was sold before flying it. Pictures are here somewhere. Pictures of number one is somewhere here also the forum is getting so big I can't find it right off.

Here is a picture of Viper 1 I found

[proparc]

Fancher had a great formula for calculating wing area. had to do with measuring all the way around the wing - total distance - then dividing by, hmm, average chord? Don't remember, but I have it written down somewhere.

Autocad, 14 decimal places if you need it.

[Allan Perret]

So Sparky:
Other than a minimal finish, what are some of the techniques in the construction that you use to build a 660 inch machine in the low 50's ??

[RC Storick]

So Sparky:
Other than a minimal finish, what are some of the techniques in the construction that you use to build a 660 inch machine in the low 50's ??

Every piece of everything was weighed before it went on this plane. I had made 3 stab and elevator combos and chose the lightest one. Every piece of wood was weighed. Wheel pants are the lightest ones that can be bought. The .40 size landing gear was thinned down on a belt sander.Warren truss wing. Molded turtle deck and Leading edges. As this plane was a experiment in its final stages I really did not take as good a care in sanding as I could have. The final version (which is next) will have a better finish and hopefully lighter. I think I am on the outside of the weight issue with the current power train available. So I don't think I can make it much lighter a ounce or two maybe.

[Randy Powell]

I never have problems with creating a light airframe. My last plane, a 640 square in plane, ready to fly with engine, tank, gear, prop, etc. but unfinished (just bare wood, not even a coat of clear) weighed 37oz. with wheel pants. Problem for me was, I decided to experiment with paint again (man, I have GOT to stop doing that). So, ready to fly weight was 64oz. That's 2 and a half pounds of paint. I didn't even think it was possible to do that.

So, it's sitting on the rack awaiting being stripped and refinished. I think I'll cover it, clear coat it and fly it. Might paint a canopy on.

[RC Storick]

Paint will surprise you. I should say finish. When I was finishing this plane I set a weight of 48oz with the .40 in it. I kept weighing it and when it hit that weight I stopped. It finished out at 47.5 then the big block was added which was five ounces more total with pipe and tank. Now with trim changes its 53.5. It really needs a coat of urethane on it but I have abstained the thought of that. Its hard for me. The dope shines but not like the other. I will not do this because I know it will end up 60+ ounces and this is not what I seek.

The trick is on the next one to sand better and make it lighter so I can add more paint and achieve close to the same weight or lighter with a better finish. A world champ told me "people who say lighter planes don't fly better probably have never built one".

I was asked by Jim Lynch after appearance judging a few years back "How I got a plane of this size so dam light?" He had been speaking of my S6B that at that time was 58 oz. I didn't like that plane as the nose was too short. Ron wanted me to get the concentrated weight closer to the CG and it would have worked if it was 3 or 4 oz lighter. Instead I had to add nose weight to balance it only making the feeling I am trying to get away from worse. I did let Mr. 69 NATS fly it and he said it was point and shoot.

[billbyles]

I never have problems with creating a light airframe. My last plane, a 640 square in plane, ready to fly with engine, tank, gear, prop, etc. but unfinished (just bare wood, not even a coat of clear) weighed 37oz. with wheel pants. Problem for me was, I decided to experiment with paint again (man, I have GOT to stop doing that). So, ready to fly weight was 64oz. That's 2 and a half pounds of paint. I didn't even think it was possible to do that.

So, it's sitting on the rack awaiting being stripped and refinished. I think I'll cover it, clear coat it and fly it. Might paint a canopy on.

Ahhh, Gordan Delaney may (or may not) chime in here and tell us about the stunter he built and finished a while back (sort of SV-11ish).  He went to apply the 2-part polyurethane clear and mixed up nearly a half-gallon.  Well, he got it to where it looked gorgeous and still had quite a bit in the gun so he thought "well, I'll just put a couple of more coats on...and so on" (and since there was still quite a bit left in the mixing can...extrapolate here).  He came to a contest at Whittier Narrows and wouldn't tell me what it weighed.  Several years later he admitted that it weighed north of 75 ounces. 

I couldn't tell this story on Gordan except that I did the same thing with a Skylark that I scaled up to a .60 size at 720 square inches (I used a Randy Smith O.S. .46VF and pipe) that ended up at (don't look now) 78 ounces.  Never again!  I flew it at the 95 Nats (18th) and at the 96 Nats (20th, if I remember correctly) but it was a chore to fly.  So I know exactly where you are coming from, Randy.  I didn't have the heart to refinish it and gave it away after awhile.

[RC Storick]

A great series of airplanes, Sparky.  Just because it's sort of "my" thing I'd be interested in the aerodynamic progression of the series; i.e. what you changed and why from version to version?  Which things worked and which didn't for you?

Ted

Viper 1 was a old airframe concept with a muffled engine Straight foreword. #2 was coming in the realm of modern numbers with old ideas 1 inch swept foreword TE. and a muffled super tiger The wings have always been my own plan form of sorts. #3 was the first of the VF.40 piped I beam planes. I crashed it 2 weeks before SIG and needed a plane so # 4 was born in a hurry. If I remember right it had a SV foam wing in it with Xkote. There are a few Vipers missing in this as I think about it a white one and the Super Glide.

I have been all over the place with numbers. Thrust line. Stab (there was a in-line Viper), wing cord and tip cord, Straight trailing edge and tapered. So far the Tapered TE has worked the best. So my numbering system is lacking. The next one will be exactly like the one I have now as it is by far the best of both worlds.

[RC Storick]

here is a few shots I dug up.

[RC Storick]

I have been cleaning my shop the last few days and tonight I found this picture. I thought there was only one pic left of number three. So it looks like old age is setting in. I have missed count on the Viper series. Number 8 should have been 11. So to simplify things no more numbers.. Besides I am done with changing things.

[Ted Fancher]

Viper 1 was a old airframe concept with a muffled engine Straight foreword. #2 was coming in the realm of modern numbers with old ideas 1 inch swept foreword TE. and a muffled super tiger The wings have always been my own plan form of sorts. #3 was the first of the VF.40 piped I beam planes. I crashed it 2 weeks before SIG and needed a plane so # 4 was born in a hurry. If I remember right it had a SV foam wing in it with Xkote. There are a few Vipers missing in this as I think about it a white one and the Super Glide.

I have been all over the place with numbers. Thrust line. Stab (there was a in-line Viper), wing cord and tip cord, Straight trailing edge and tapered. So far the Tapered TE has worked the best. So my numbering system is lacking. The next one will be exactly like the one I have now as it is by far the best of both worlds.

Interesting, Sparky.

I was more curious if you had tried things that would help out in your search for better lift to weight ratios ... other than constantly striving for ever lighter ships.  Monitoring Denny's long winged electric gave me a classic example of that.  If you were to increase the span (for the same area ... and keeping the same very reasonable weight [IMHO] to something like an aspect ratio of six or 6.5 to one) you'd get significantly more lift for a given angle of attack which would help you reach your goals without having to sacrifice the finish that is important to you.  Induced drag would also be reduced commensurately for a given rate of turn which is also one of your goals.  The reduced drag would have another benefit in that such a ship wouldn't require as much BMEP up front which could mean a smaller, lighter engine which would also burn less fuel.

Just thinking out loud.

Ted

Ted

[RC Storick]

Thanks Ted I had thought of that. However around that time I owned two of Jim Cassel's Spectrum's which were HR wings and they were light. 57 and 58 oz Super-tiger .60 powered. The had some bad chartists I did not care for so I went breasty in cord with a few. Thinning out the tips with a tapered TE.

Dennis Adamisin plane is a beautiful ship and I would be interested to see it finished in dope. X Kote is going to be lighter. Its just not for me. Paul Walker handed me his plane a few NATS back and said with do you think of this weight? It was light but were was the battery? LOL

[dave shirley jr]

Hey Brett
I have allways figured area by adding the tip and root cords flaps included and then multiplied by half the span.
on offset wings i use the average span.
then add tip area.I sort of estimate the cords and span of them depending on the shape.
I think it is acurate since it basically assumes a parralellagram.
does this sound right? if not ive been doing it wrong for a long time.
i compared the autocad measuring to my way once and it seemed to agree
i also used to figure area of a circle PI*R squared until a friend who worked as an engineer for lockheed told me it was supposed to be PI*D squared /4
but near as i can tell its the same formula
Dave jr.

[john e. holliday]

Sparky, if you quit changing things I would be very surprised and think you have given up.

Now measuring wing area, I never though of using paper or card board to figure out wing area.

Learn something everyday.   DOC Holliday


PS:Now if I could only remember it.  jeh

[Bryan Higgins]

Robert

The Viper planes are some of the best designs i have seen.  To me your plane the Viper
should be a plane for sale in a kit at what ever Control line store there is.

I would buy it      Bryan Higgins

[Ted Fancher]

Fancher had a great formula for calculating wing area. had to do with measuring all the way around the wing - total distance - then dividing by, hmm, average chord? Don't remember, but I have it written down somewhere.

Hmmmm, not me, Randy.

Somebody once ran a similar idea by me.  His idea was to simply run a string all the way around the circumference of the wing.  Tie a knot where the ends meet; then form the length of string into a square or, for that matter, any conveniently sized rectangle.  Final step was to measure the side of the resulting square and then multiply it by itself (ie, mathematically square it or; multiply the short side of the rectangle by the long side) to obtain the area in square inches.  The resultin number would be the same area as the wing. 

Sounded really logical and simple until I suggested that if he make the rectangle real long and narrow.  I.e. say the wing is a sixty inch span with an average chord of eleven inches (pretty common "modern" numbers). So the leading edge is about 61 inches long; plus 61 inches for the trailing edge plus lets say 12 inches for each wingtip.

O.K., total that length up and you've got 61+61+24=146 inches of total string length.  Now, stretch that into a rectangle that is 72" long and one inch wide.  Multiply one inch by 72 inches and you get an area of 72 square inches.

Ooops!  So much for the string theory.   

Ted

 

[Doug Moon]

Measure across the wing (less tips) multiply by tip cord. Subtract tip cord from root cord times that number by half span = total wing area less flaps and tips. Do the same for flaps. Because tips are rounded you can figure it close the same way doubled. Add them all together and wallah total area..

Come on Brett I know that you know a better way?

I cannot follow this.

span (sans the tips) x tip chord = x

Tip chord - Root chord = y

y x 1/2 span = area.

Huh??

[RC Storick]

Ask me at the NATS

[minnesotamodeler]

Add "x" to what you have labelled "area" and you have it.

[Dick Fowler]

Robert, I have a question.

Looking back on this latest NATS and the performance of your current Viper, what changes will you make on the next version of the Viper and why?

[RC Storick]

Its going to have to be bigger and more colorful so old people can see it! 

[RandySmith]

Hmmmmm... and all this time I thought you were building a new SS-75...

Randy

[RC Storick]

I am 

[Matt Colan]

Its going to have to be bigger and more colorful so old people can see it! 

I would think, white, red and blue is easy to see.  What about checkerboard, and white, red and blue (colors for my Oriental Plus), those seem like they would light up in the sky.

Hmmmmm... and all this time I thought you were building a new SS-75...

Randy

SS-75???  what does SS stand for?

[Brett Buck]

Robert, I have a question.

Looking back on this latest NATS and the performance of your current Viper, what changes will you make on the next version of the Viper and why?

  Sparky and I worked on it for a while at the NATs, and while it was somewhat out-of-trim, there's nothing that couldn't pretty easily be fixed. It was built very nicely and all the parts of a very good airplane are there. And I think it is almost ideal as far as size goes. I'll let Bob elaborate if he so desires.

     Brett

[Larry Cunningham]

It's a lovely design, IMO. And I really like your paint schemes.

Something about a classic stunter.. lifts the heart

L.

"If you don't want to work, you have to work to earn enough money so that you won't
have to work." -Ogden Nash

[Howard Rush]

  Sparky and I worked on it for a while at the NATs, and while it was somewhat out-of-trim, there's nothing that couldn't pretty easily be fixed. It was built very nicely and all the parts of a very good airplane are there. And I think it is almost ideal as far as size goes. I'll let Bob elaborate if he so desires.

     Brett

I was impressed, too.  I did notice that both Sparky and I were hitting corners a too hard at times.  After I got home, among other changes, I reduced the line spacing at the handle just a little, which I thought helped that tendency a lot.  I thought I'd suggest that to Robert.  However, after getting my airplane into what I thought was pretty good trim, I let the stunt ED of the recent Nats fly it today.  He said, "It's a nice plane for sport flying, but unsuitable for competition."  I guess I have some more work to do. 

[Jim Pollock]

Howard,

That would be unsuitable for "Paul" to fly in competition.  Preferences as to trim and balance of models is dependent on reactions of individuals.  What may be unsuitable for competition by Paul in this stage of his modeling and flying could actually be quite suitable for yourself.  Keep working and you will get to the point where you can tell the difference in performance of engines by increasing/decreasing nitro by only 1/2 of 1 percent and tip weight by 1 gram or less.  After you have flown thousands upon thousands of practice flights after changing something on your plane and "carefully" observing the effects then you will be there!

Jim Pollock 

[john e. holliday]

Howard,  everyone has their style and sensitivity to flying a plane.  Has your local stunt guru let you fly his plane that is in full trim?  I flew my plane at the field yesterday one time after playing with the Slob.  The handle was off a little in which I had to hold a little up.  Everything was going great and looking like I had listened at the clinic earlier this year until the vertical 8.  The hip let me know it was still there.  Almost lost the plane.  Should have known better after dinging the Arctic Fox earlier in the week.  The pain pills did not work.

As far as size of planes I didn't think the new Viper was that small.  I also love the color scheme.  Was it the smallest plane at the NATS.  Not being there I wouldn't know.  Maybe it is just some little kink in your pattern the judges did not like.  But, I think I can understand your disappointment in your results at the NATS. 

Anyway I hope you don't give up, either of you as I think both you guys are terrific competitors as well as gentlemen.  DOC Holliday

[Steve Fitton]

... I let the stunt ED of the recent Nats fly it today.  He said, "It's a nice plane for sport flying, but unsuitable for competition."  I guess I have some more work to do. 

?  What did he specify as being "unsuitable"?  Do the flap tabs taint it in some way?  Does it require a VF to be perfect?

[Larry Cunningham]

We definitely get tuned into our models. If you want a demonstration, change the neutral setting on a friend's handle just slightly without telling them (not at a contest!). They'll tell you just how messed up their ship suddenly was, and what a mystery it was.

That said, there's the issue of trim, which goes far beyond preference. A trimmed ship can realize its true potential, theoretically. A couple of experiences at stunt clinics, where the very good flyers spent some time with my model convinced me of the value of good trim - I came away all charged up about my ship, and I enjoyed seeing the model so well flown by people who obviously knew what they were talking about.

Bill Melton was the first to give me some very serious help with trim, and he told me that many potentially very good models never got proper trimming, and went undiscovered by their builders.

The other thing I noticed early on is that the best flyers are constantly trimming, at least a little, on their models. Flying conditions change!

L.

"What a long time I have been running after unrealities!" -Jitoku Eki

[john e. holliday]

Lalrry,  juntil the last few years I never knew that Bill Melton flew stunt.  I always thought of him as a Navy Carrier flyer.  I will never forget the first time I met him at a NATS.   Maybe you need to put him in the  Stunt Grunt thread on this site.  DOC Holliday