Snagletooth Flies

LAST EDITED ON Nov-09-04 AT 12:36 PM (CDT)
 
Well, like other projects which take an inordinate amount of effort to complete, it is a joy and relief to finish this project. Richard Oliver was visiting from Houston to work on his new design and watch Snaggletooth's first flights.

The first test flights didn't proceed exactly smoothly. To insure a safe groove and extra line tension, I added 1 1/2 oz of noseweight and 1 1/2 oz extra tipweight over and above the built in 1 1/2 oz. The first three flights were so rich I couldn't even loop. I tried leaning the needle, and finally threw away the old venturi filter thinking it might be blocking and "choking" the engine. The third flight was flown with the needle closed tightly, and the engine still ran. That was the beginning of understanding. We went home, took the engine out, verified the needle would shut off the fuel, and finally discovered the problem. The needle valve extension was bottoming out on the fuselage side. With that fixed, we headed back to the field.

At the field, the engine started and ran normally so I was able to do a pattern. Snaggletoth "locked" in level flight and maneuver straight lines but lacked a really competitive corner. It was safe and fun to fly but took entirely too much effort on the handle to get a halfway decent corner. The nose weight was reduced and finally removed which helped the corners without hurting the groove, but it still wasn't enough. Richard and I agreed that the exceptionally stiff flaps were overpowering the elevators. Still, it was fun to fly and Richard and I both put in flights before calling it a day.

On Sunday, at Hobby Park we joined other Dallas flyers for a session. Richard suggested that "taping" the elevators might improve elevators effectiveness to improve the corners. We tried it and BOY, DID THAT WORK! Now Snaggletooth turned like a combat ship, so much so that I was able to put a bit of noweweight back on. Also, now that there was a hard corner Snaggletoth was noticably "hinging" from the excess tipweight. I removed some, and it helped but there will be many fun flights fine tuning the trim. So far, I haven't started to trim the rudder or leadout location. Except for a bit of removable wiggle here and there, it is already the competitive airplane I hoped for.

Bottom line. Snaggletooth turned out to be all that I had in mind when I decided to update a NATs champion airplane. There is still a bit of trimming to do to fully realize my goal but the goal is clear. It flies "locked in" stable with really nice rounds and all the corner needed for "modern" maneuver size. Having double the power of the original airplane gives the new Snaggletooth noticeably more drive and line tension, particularly in vertical and overhead maneuvers.

It has been a year long project which didn't always proceed smoothly, but it was certainly worth the effort.

Al

BRAVO! It's just beautiful.

Glad to hear taping the hingelines proved valuable.

Dear Santa,
I have been good all year. ( OK, except that one time....)

Please put this under my tree this year.

When I started considering flying stunt I read an article by Bob Hunt on FM Magazine recomending hingeline taping.

My coach was a Bob Hunt fan, and
he told me that whatever Bob said about stunt was to be taken as gospel truth.

As a result, I must confess that I have never flown a non-taped ship, so I can't really tell the benefits of tape. I'd have to try a ship without taped hingelines.

"Taping the hinge line" fixed the problem. Please give me some details as how this was actually done. What tape? Both sides? Any details? Thanks.

Very nice!!!

Tnx, Mike, the "Old Harley Man" [email protected]

Norm,

This is a very common procedure to tape the flap and elevator hinge lines to improve performance. The most common target is the flap hinge to wring a bit more lift out of the wing.

Mainly, you apply tape to the bottom of the hinge line after deflecting the control as far as it will go. Most clear plastic tape seem to work fine. We used "magic Mending" tape. Richard did the honors as I haven't used or needed it is the past and am not expert in its application.

On my classic plane, it was clear that it just needed more outboard flap. I added a small tab and it was better, but it was not enough. Taping just the outboard flap pretty much cured the problem. Just that extra bit of lift out there did the trick.

Taping control surfaces is an oft used trimming tool.

Hi Al....I forgot to ask what you're using for power....Masterful construction!

Tnx, Mike, the "Old Harley Man" [email protected]

Mike,

For now it is flying with a PA 65 and a hand carved 14.5-5" prop.The engine runs and performance are all that I hoped for. Still, I have the very first Ro-Jett 77 which will fit the existing mounts. It is only a matter of time.

Hi Al,
Superb, and glad to hear that it is going to meet, or exceed, your expectations!
Bill <><

Just wonder: What is the weight..?
Norvald Olsvold

59 ozs, 590 sq ins. It works if the flaps are effective enough.

OK. That is exactly the same wingload as my Inttrepid XL
(67 OZ ,670 Sq"). I was afraid mine was far too heavy..
Norvald Olsvold

Completely awesome, Al. Congrats on a wonderful project.

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"Great minds have purposes, little minds have wishes." -Washington Irving

Al, would you mind giving us details on the landing gear "shock absorbers" ?

I think it's good for humanity that you spend your mental capacity making those awesome ships.

A mind like yours if used the wrong way could be a danger to the planet!

(this is suposed to be a compliment)

Ion (in bewildered awe) Muniz

LAST EDITED ON Nov-09-04 AT 09:24 PM (CDT)
 
Ion,

The gears are very simple. The strut which mounts the gear to the wing is 1/8" music wire. The other two struts are 3/32" M.W. The brass bushings may be attached to either the fixed strut or movable strut depending on whether the gear is to move with the door like the Bearcat or move behind a fixed door like the Mustang. Shock gears weigh about .4oz more than a 1/8" wire strut. The optimum application is to use very weak springs which are barely able to hold the struts extended when the airplane is inverted. Stronger springs tend to make the airplane "bouncy". They take about two hours each to make with a simple jig. I use springs 1 1/2" long, .011 wire, 5/32" coil diameter. The brass bushings are "figure 8" wrapped with fine copper wire and soldered. The assembly trick is to assemble the finished struts with force as necessary then heat the bushings with a torch and watch them self align. Clean the flux from the bearings with thinner to farther free up the gear.

Many people will attest that these gears work extremely well to make the takeoffs and landings high scoring and, to some degree, defeat surface irregularities.

Since they obviously work so well, I was never able to understand why they didn't become wildly popular. Oh well, the scoring advantage was always mine.

>The gears are very simple.

Al, while I agree that the design is elegantly simple, the soldering work is likely to be challenging to many folks.

Your models are labor-intensive, and you clearly love that labor. This is what defines a master modeler.

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"Nature gives you the face you have at twenty. Life shapes the face you have at thirty. But at fifty you get the face you deserve." -Coco Chanel

Bet I can guess what Bill Rutherford's next project will be.

Beautiful work, Al.

Ralph Wenzel

Bill has a Snaggletooth kit but prefers to build classic. Snagletooth is a 1973 airplane.

LAST EDITED ON Nov-09-04 AT 10:09 PM (CDT)
 
I had an interesting experience on Snaggletooth's second flight. Immediately after starting the engine it was obvious the stooge had released. I was saved from injury by having a firm grasp on the forward fuselage with my left hand. I couldn't believe it. I am obsessive about stooge engagement and religiously check it without fail before starting the engine. Still, it was loose. I yelled to Richard to reengage the stooge. He did, and the subsequent launch was uneventful.

I just couldn't believe I had failed to engage the stooge or that I failed to double check it prior to starting. I finally decided that maybe I had failed to engage the hook while fastening it without my reading glasses and wrote off the failed double check to old age. I guess it happens.

That afternoon, while starting, I noticed the stooge had released again. One time maybe, twice in one day, impossible! Inspection revealed the stooge hook was made from .032 wire and was forced open enough to pass the stooge retaining wire when the airplane was pushed back by the starter.

Well, old age dose take its toll. I couldn't believe I had used such a thin wire stooge hook. I have a number of the .032 hooks. They came with the stooges twenty five years ago when Dirk Tollennar made them for me but, I changed to .045 wire when I started flying 60 size airplanes and bent them myself. Every airplane currently in my possession except a Mustunt have .045 wire. I really can't say how that thing wound up an my newest airplane.

The moral is obvious. We have to take extreme measures not only for our own safety but to preserve airplanes hard to replace. I goofed. It is fixed. I'll try to be more careful in the future.

you'd BETTER be carefull! That plane is OURS!

BIGS

" What constitutes the dignity of a craft is that it creates a fellowship, that it binds men together and fashions for them a common language. For there is but one problem - the problem of human relations."

Why would you use a stooge with your flying partner right there with you? It seems it would always be safer to have Richard hold then a stooge.

Good question, Doug!

LAST EDITED ON Nov-10-04 AT 10:27 AM (CDT)
 
As Doug stated why a mechancical stooge when you had a real life one with you. Also are you now going to come out and show the youngsters how to win the Nats and all the local meets again? Be great to ;see you trounce all the kids again. Later,DOC PS: That is one gorgeous airplane, can't wait to see it in person.

LAST EDITED ON Nov-12-04 AT 10:57 AM (CST)
 
I have seen so many airplanes damaged by improper handling and poor releases that I have a strong preference for the safety of stooge launches.

I built the airplane and know where it is strong enough to withstand handling. There are areas like the inboard wing leading edge that were strengthened to tolerate handling. The wing leading edge outboard of the gear is not reinforced. I see many launches where the airplane is held by the aft fuselage and outboard wing near the tip. this would be dangerous to my airplane. When someone launches my airplane, inevitably there is resentment when I tell them very specifically how I want it done. some people take offense and this creates hard feelings. I have had several airplanes damaged by poor launches and careless handling over the years. Poor launches where the tail is lifted or the airplane pushed are too risky. Also well meaning persons rush to help pick up the airplane to clear the circle and I wind up with cracked .077 wing leading edges, 3/32" aft fuselage structure or 1/16" tail structures. Several times I have witnessed an airplane damaged and the offending party leave without telling the owner of the damage.

Hand launches are fine if the launcher, like Richard, willingly accepts instruction about the best method. Still, stooge launches are preferred for other than contest launches. For example, when Richard and I fly together in Irving we usually, but not always, launch from my stooge. It gives the flyer safe, controlled launches and frees the other flyers to observe the flight, coach from upwind, or work on their equipment. We carry each other's airplanes to clear the circle and position airplanes for launch.

When I launch an airplane, unless otherwise instructed, I hold it, with cupped right hand, by the outboard wing against the fuselage for primary restraint, and my left hand cupped lightly on the inboard stabilizer against the fuselage to stabilize the tail. At the release signal I ONLY straighten my fingers for a stooge like launch. I don't move with the airplane or pull my hands up which is an invitation to lift the stab and cause a nose down pitch which gets the prop.

Unless otherwise instructed I pick up airplanes by the landing gear with my thumbs cupped over the leading edge of the wing to cradle but not press against the wing.

I am comfortable with Richard launching my airplane. He launched all of my takeoffs at Hobby Park. I would also be satisfied with anyone else who willingly accepts instruction about handling my airplane for launches and clearing the circle. Notice too, if Richard had been launching those initial flights, I would have been unaware of the dangerously thin stooge hook until I had an accidental release while flying by myself with no one to secure the equipment or transport me to medical care. God does sometimes take care of the stupid and careless.

I don't want to offend anyone, but stooge launches are safer to my airplanes than launches by bystanders who already know all there is to know about launching stunt ships. My structure is very thin and light. It makes me very uncomfortable to have people casually grab my airplanes without knowledge of where it is reinforced to tolerate casual handling.

If the flyers at Hobby Park would like to help me fly there, I'd appreciate it as stooges are forbidden, If they are willing to do it my way. Otherwise, I'll stooge launch at my local flying site and fly by myself as I have done for most of my Control line flying. I am sometimes joined by other flyers at my site but we all understand how the airplane owners prefer their airplanes to be handled. I have observed recently at Houston one helper who grabs airplanes by the nose and pushes them on launches and denies doing it. I think that careless handling of someone's else's airplane rude in the extreme. Some airplanes are fragile. All have fragile spots. I am not offended by instructions from the owner about launching and recovering their airplanes. Some people are offended. I would rather fly by myself than perpetuate the opinion I'm an xxxxxxx.

Handling someone else's airplane is a responsibility not to be taken lightly.

Al

P.S. I consider stooge launches the safest possible launch. The accidental releases I had were not failures of the system but my failure to install a proper stooge hook. In many thousands of stooge launched flights, I have never had an accident due to accidental stooge release. I have had an occasion where I failed to engage the stooge on a Classic Bearcat flight twenty five years ago. I remember it clearly. When the engine started, the Bearcat charged at me. I jumped to my feet. The Bearcat ran between my legs to the wing leading edges without the prop hitting me, but I did have a diaper wiping rag hanging from my hip pocket. Local visibility was immediately reduced by diaper lint. I couldn't get to the needle valve which was behind me without bending over and placing my behind uncomfortably close to the diaper chewing prop. I just stood there for seven very long minutes swearing never to let a stooge launch get away again.

Good Post!

People shouldnt take offense to launch instructions. Bob has been telling me how to do it for years. There are always thin spots on his models as well. It helps me out so I dont make mistake and cause a problem.

>Handling someone else's airplane is a responsibility not to
>be taken lightly.
>
>Al

I agree totally, Al.
I can still remember the look on Curt Contrata's face after the SECOND time that I launched, his wing had another hole in it.
Both times, a hole. They were on the outside bottom of the wing.
Later that evening he found a rather large bumble bee lodged in the wing spars. All the time I'm sure he was thinking that I was poking holes in his wing!
Not so.
Bill <><

LAST EDITED ON Nov-19-04 AT 01:33 PM (CST)
 
Snaggletooth continues to fly well as I begin to trim and adjust. It has a new stooge hook and a new metal uni-flow clunk tank using Siamese pick up and uni-flow both on the clunk. This solved the six to eight laps of surging as the tank ran dry. The engine run was and continues to be excellent with the breaking in all the right spots. With the early removal of noseweight and subsequent improvement in turn from the taped elevators, Sanggletooth turned faster than I could control it with a strong tendency to overturn corners. I put some noseweight back in immediately to improve my ability to hit an accurate line out of a corner and now I've added more to tame Snaggletoth's tendency to overtax my aging reflexes. It is smooth and groovy, but a Tiger in corner maneuvers.

Fine tuning the trimming is more difficult than I thought it was going to be. The airplane flies well and is so solid on the end of the wires that various trim adjustments seem to have little effect. Actually, it is hard to determine what else the airplane needs. Maybe after I start flying in in substantial wind, I may find ways to improve it. With power and penetration, I'm hoping this will be an ideal combination of size, lift and thrust for those windy contests. I did get the wobble out of hard outside squares but haven't accomplished much else yet. So far, I still haven't touched the leadouts. I'm flying at 5.6 sec laps on 65 ft lines turning a hand carved 14.5"-5" at 7700. Line tension is great everywhere, particularly in the top of the vertical eight, hourglass, overheads and cloverleaf. I feel strongly this is the result of dramatically increasing the power compared to the original Snaggletooth. I have found no adverse effects from running the .65 in my 59 oz, 590 sq in airplane, except the power of the airplane is a bit intimidating. Snaggletooth and I aren't friends yet but with time and practice, we will be. Then it will be time to try my Ro-Jett .77 (which fits PA and Ro-Jett .65 mounts) for even more excitement.

As I get around other modelers, I'm sure there will be reports on the unusual capability of this airplane. With attention to good aerodynamics, light construction and lots of power, competition stunt ships can be designed with enough semi-scale realism to be interesting. To make that point, Here are a few photos which better illustrate the moments and areas of Snaggletooth. With its very nose up attitude on the ground, you might think that would make for awkward stooge launches, particularly, since the engine turns that big prop at nearly a steady two cycle until Snaggletooth is airborne with the engine loaded. Actually, the tail pops up on launch and Snaggletooth accelerates like it was shot out of a gun. The engine doesn't really settle into its strong four stroke until Snaggletooth levels about a half lap from launch. If control were needed on takeoff, it would be virtually uncontrollable, but it leaves the ground after about a quarter lap and climbs smoothly to level off mostly by itself. Thank goodness, all I have to do is to hang on.

Hi Al,

Really nice plane! Sorry to hear about having so much trimming troubles though. My ahhheeeemmmm, brilliant idea is that since you have a PA .65 in the nose, why not try using a 4.5" pitch prop and a few more RPM's? That might be a little help in stabalzing airspeed somewhat during maneuvering. That might be a little help with trimming?? Of course all the trimming problems could just as easily go away with the insertion of that RO Jett .77 into the nose too! I know for a fact that all your models have as much or more corner than can be aequately controlled. I've watched Keith Trostle fly his Classic Bearcat and the corner it produces is absolutely incredible!

Regards,

I couldn't be happier with my engine run. flying a "draggy" semi-scale is usually improved by having a nice 4-2 break and a big prop with a large disk area. I love an airplane with "drive" and am able to accelerate back to maneuvering speed while climbing vertically following deceleration from drag in a hard corner. My trimming problems lie in the airplane being so solid on the end of the lines that it is difficult to observe results from changing trims. Basically, it flies well however I trim it. I should have had such "problems" with the original Snaggletooth at the World Championships in 1977. Tim Allen has it right. More power! More power!

I like the profile view the best, it really shows the beauty of the machine and its lines. Great job!!