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F.Y.I. APRA Rules Enforcement At Whittier

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F.Y.I. APRA Rules Enforcement At Whittier

Old 05-24-2002, 02:24 PM
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Stan Shoun
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Default F.Y.I. APRA Rules Enforcement At Whittier

As some of you know, we had our first protest of a TT Pro 40 engine during our past races on May 8 & 9. To make a long story short, the engine in question was box stock with one exception. The low speed idle screw had been ground or cut off so that it no longer protruded into the throat of the carburetor. The explanation offered was that this modification was only done so the engine would shut off at the end of the heat when the throttle and throttle trim were pulled back..... possibly this situation was brought about due to a bad muffler bearing or maybe the crank was cranky..... or maybe the real intent was to improve air flow through the carburetor so as to gain a performance advantage After a conference was held amongst club officials, it was decided not to declare the engine illegal THIS TIME. Our rational came from one very lame source only.... this was our first engine protest in two years since our club got back into pylon racing and rule enforcement at both our field and at Sepulveda Basin (Valley Flyers field) had pretty much been on the honor system (bad plan to trust any racer that much on a regular basis) for quite some time. We felt if we declared the protested engine illegal at that time, we would likely be faced with going down the line and finding quite a number of others illegal as well. We were in a bad place and the blame belongs entirely on us as administrators of the rules.... not the racer being protested. I'm a competitor too and if you gimme an inch, I'll turn it into a mile IF YOU LET ME. In any case, we decided to let it slide that time and then give everybody fair warning that such things WILL NOT BE TOLERATED in the future. I personally also saw a couple of TT Pro 40 mufflers welded together and even though I understand the most logical reason behind such a thing is to prevent loosing the tail cone and not for a performance advantage, the fact remains this is not box stock and is obviously severely modified. Therefore in summary, for all future APRA events held by our club, SGVRCL at Whittier Narrows, you must have a stock low speed idle screw installed and it must not be altered in any way. Back it out till only half a thread is holding it in if you like, just make sure it doesn't fall out or you will be disqualified, if caught Welded mufflers also will no longer be allowed unless you are prepared to cut it apart on demand. It's just not good enough to stick a dowel up the tip to see if it hits SOMETHING such as the baffle. We must be able to disassemble the muffler for a complete inspection should it become necessary for whatever reason. Don't forget, the CD can check anything at anytime just because he/she feels like it. In closing here, I want to make it crystal clear, we are not trying to get nit-picky about rules. We just want to take temptation out of the hands of a few and strongly encourage everyone to leave these motors alone! Per the AMA rule book, you can change bearings, gaskets (head shims) and the nuts and bolts..... NOTHING ELSE! Our belief is the main focus for this class should be directed towards your thumbs/flying skills which everyone seems to agree is at least 95 pecent of the battle. I've had lengthy discussions with Barry Leavengood of the Valley Flyers Club at the basin and would suggest everyone get ready for uniform rule enforcement at both of our fields. I'm sure Barry will make his own comments to this effect as well.

Thanks for your time and understanding,

Stan Shoun
CD - SGVRCL
Old 05-24-2002, 03:46 PM
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Bill Vargas
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Default The Rules

Stan, if you are in need of NO-GO gages or some other specialty tool,,, for checking engines, airframes and wing thickness,,, just let me know!

I will be more than happy to step into my Machine shop here and whip something up

I take it, The Rules inforcement applies to Sepulveda Basin as well ?
BV
Old 05-24-2002, 05:08 PM
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Default F.Y.I. APRA Rules Enforcement At Whittier

Bill:
See my post on the NMPRA Forum.



Barry
Old 05-26-2002, 12:05 PM
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Bill Vargas
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Default The Rules

Originally posted by bl10
Bill:
See my post on the NMPRA Forum.



Barry
Thanks Barry!

I wonder if other clubs out there are doing the same???

BV
Old 05-27-2002, 02:19 AM
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MaxQ
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Default TT Pro Muffler Modifications

The last two TT Pro 40 I have purchased have experienced similar muffler failures. The 5 inch long threaded 4-40 type fastener keeping the muffler together has sheared internally. The first engine on engine fight 40 the second engine during tank number 3 during break-in??? My solution has been to drill and tap the aft end "bullet" to the forward muffler body. No muffler flow characteristics have been changed, the baffle remains in place as purchased. Does anybody else have this problem or am I just a moron.





MaxQ
Old 05-27-2002, 02:24 AM
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MaxQ
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Default Addendum to TT Pro 40 Muffler Modification

Forgot to ask the question. Is this modification within APRA rules????

MaxQ
Old 05-27-2002, 05:05 AM
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Bill Vargas
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Default The Rules

Max, Yes, drilling and using sheet metal screws to keep the muffler together is aceptable,,, Reason is that the muffler can still be taken apart for an inspection.

I have also found that The Magnum 60XL muffler thru bolt is a perfect substitute for when the TT bolt can t be found

BV
Old 05-27-2002, 10:23 AM
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Stan Shoun
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Default F.Y.I. APRA Rules Enforcement At Whittier

Max, To the best of my knowledge, Bill's interpretation of the rules is correct regarding using sheet metal screws to hold the muffler together however I have not had this confirmed by the APRA rules committee. Possibly Jim Allen, Gary Schmidt or Stan Douglas from the Arizona based APRA rules committee could jump in on this thread and enlighten all of us, "From the Horses Mouth" so to speak. The problem we run up against in such things is how strick does one interpret the phrase "Unmodified or Box Stock" Obviously the muffler does not come new out of the box with sheet metal screws in it. AMA rules say you can change bearings, gaskets and bolts. Does this mean adding additional bolts/screws beyond what the manufacturer shipped it with (?) or is the criteria based on whether or not a modification could or would result in a performance advantage? Clearly this is a gray area and needs a definitive answer from the powers that be on the APRA rules committee. As Bill pointed out above, unlike a welded muffler, you can always take the screws out and still disassemble the muffler for internal inspection if the need arises.

Another solution to this problem, which has been discussed in a previous topic on this forum, and I know is legal, is using Permatex Hi-Tem RTV silicone Gasket Maker material. I personally like the "Ultra Black" however Don Stegal found "Ultra Copper" which evidently will withstand higher temperatures. I've used both and ended up going back to the Ultra Black just because it seems to have much stronger adhesive characteristics after it sets up and is completely cured, which is what we're mainly looking for in this application. I've lost tail cones too and just the same way as you, the bolt sheared inside the muffler. I haven't had the nerve yet to try running one without the bolt at all and only using the Ultra Black however I can tell you it takes quite a pull to get them apart for cleaning/maintenance after they've had a few flights and the stuff is completely curred.

Stan Shoun
CD- SGVRCL
Old 05-28-2002, 03:25 AM
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Tony Pacini
 
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Default TT PRO40 Modifications

These questions (good ones, I might add) have been asked before. Remember that the INTENT of the "stock engine" rule is to prevent racers from improving performance. Jim Allen has said that he will allow glued, welded, or bolted mufflers (these modifications should only improve durability and save everyone money.....a good idea in an entry-level class). His test? Run the muffler then check it against a known-stock muffler. If there is any gain in performance (which there shouldn't be) then the modified muffler will be allowed.

A few people have had problems with the carb barrel retention bolt breaking or falling out; the carb barrel slides out, the engine dies, and the spring usually finds its way into the engine (damaging the case and crank). Solution? A rubber band holding the barrel onto the carb in case the bolt fails. Many are even removing the spring. While these simple modifications just keep the engine falling apart they are still MODIFICATIONS. Should they be allowed? I think so. There is no performance advantage other than keeping the engine together. It is my opinion that such modifications will not hurt the class and should be allowed. does anyone have an official ruling on this?

How about bearings? We used to change them because the stock TT bearing would fall apart and ruin the engine. Installing the good Boca bearings gives improved durability and performance (even if only by a few hundred rpm).

What happened to the engine claimer rule? Wasn't it designed to keep racers from investing too much time (or money) in their engine (knowing that anyone could claim their "ringer" for $100?).

Comments, anyone?????????????/
Old 05-28-2002, 04:54 AM
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Default Mufflers

I do not have a problem with the screws through the side of the seam or the RTV fixes. The rules do not officially allow it, but that can be fixed with a revision very easily for the APRA. I do have a problem with the welded mufflers for the discussed reasons of inspectability.

Good job to Mr Vargas for finding a good replacement screw.

Part of this problem is caused by the fear of the problem happening. This causes people to over torque the screw. If you think about it, once a person or his buddy have had a muffler come appart, they seem to have a lot of them in a much shorter period of time than it took for the first one to happen, because they start over torqueing. We have seen this many times in the past. Think about it.

You are much better off using lighter torque with a strong locktite and maybe the RTV on the seam. I like that too and feel that should be allowed as well, as long as the muffler can be disassembled for inspection. If a muffler is inspected and can not be disassembled, the person should be disqualified.

There are tools to inspect the inside of a muffler without opening it, but they are a little expensive to be having at races.

I will discuss the proper wording and work on a revision to clairify this issue. See you at the BASIN.

Jim
Old 05-28-2002, 10:09 AM
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Default F.Y.I. APRA Rules Enforcement At Whittier

Hi Guy's and Gal's;
I've been watching this thread and I agree with about everything thats said.
In the old day's when Rossi's were the Q-500/40 engine of choice as well Webra Q-'s. AMA had no problem with us welding the muffler shroud, as this was a preventive measure not a modification. Idle stop screws on the Rossi's were notorious for breaking the nipple off, so and after market Royal Chrome Idle stop screw was found to replace the standard black that came with the Rossi. These also were found not to be a modification, just preventive maintenance.
Rule for modification as some have ref: A good engine man or woman/CD/Inspector, if need be can tell pretty quick by harmonic's, Rpm, calipers for measuring carb intake etc. on whether the engine was modified or just repaired.
I see no reason to condemn someone for preventing a piece of metal from flying off his aircraft at 100+ Mph.
Old 05-29-2002, 06:24 AM
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Default F.Y.I. APRA Rules Enforcement At Whittier

Stan & Barry.......First of all, I would like to say thanks for all the hard work putting on the Southern California races. Without you Spark Plugs, there wouldn’t be any races....... I would also like to talk a little about the clipped Idle adjust screws, and welded mufflers that have been coming up in APRA discussion. Gino’s APRA engine was protested by some contestants, at the last Whittier race, so $25 was put up to look at it, Barry, with help from the Whittier officials inspected it, and found it to be legal, so Gino picked up an extra $25. There was a question about the Idle adjust screw being clipped. I told them I had clipped it with wire cutters, for a few reasons, and Barry said he was not going to declare it illegal, simply because of this. I appreciated that. Yes, clipping it, could slightly increase air flow in the carb, but simply screw a stock needle almost all the way out, and you accomplish the same thing. With it screwed almost all the way out, there is no restriction either. You could use Silicone, Epoxy, Loctite, etc. to keep it from falling out. I had seen other guys clip them, and I did the same thing, and for quite some time. What I like most, is the fact that with the idle set as rich as possible, it is easier to shut the engine off, and shutting it of rich is better for the engine. Most Pylon engines, never idle anyway. The most important reason, in my opinion is, with the idle set real rich, if you get a lean needle, you can still stay in the race by throttling back, and maybe still pick up some points. Plus you won’t burn up your engine, trying to finish...... We did not have a welded muffler, so I don’t know where that started from. The muffler, in my opinion, should be able to be inspected. I think the TT’s run better with the baffles in them. Jim is right. Most muffler failures, are due to the long screw breaking, from being over tightened. I tighten mine to about 12 in lbs, Loctite it, and even rough up the threads, behind the nut, so the nut cannot back off. The Nylon in the lock nut melts with heat , and it can loosen. I use high temp Silicone, to help keep the tail cone on. The $25 protest bonus was nice, but nothing new. This was the seventh time, my engines have been protested, torn down, & declared legal. One was even claimed for $100. Gino’s engine had a set of Bocca bearings in it, and they were about $40, so claiming it for $100 would be a steal for someone. I don’t know why more guys don’t take advantage of the $100 claimer rule. Go to a race, decide who is fastest, and claim it .......One word of caution though....Be careful it is not just a good pilot making it look fast. A good, smooth, tight course, can make it look a lot faster than it is. I would claim the engine from the pilot that is flying like a Bat, all over the sky, and still keeping up. Now that’s horse power.....
Old 05-29-2002, 03:05 PM
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Default F.Y.I. APRA Rules Enforcement At Whittier

Mike,

Thanks for the additional information. I was wondering about the cut-off screw being an issue, because as long as it is held in by one thread, the length of the screw isn't an issue. As you said, it accomplishes the same thing. Instead of having to use an adhesive to keep it in place, the cut-off screw allows you to tighten it down.

>> I would claim the engine from the pilot that is flying like a Bat, all over the sky, and still keeping up. Now that’s horse power.....
Old 05-29-2002, 11:29 PM
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Default F.Y.I. APRA Rules Enforcement At Whittier

MDP: Those initials sound like a Voodoo Witch Doctor that passed thru Colorado a while back. Cutting off idle screws on the poor TT. Tsk,Tsk. What next magic man, filling in the TT motor mount holes for more speed? Iceman doesn't need any more help. A couple more TT tips: Removing the .016 head shim can cause piston interference and would recommend adding a .005
back in. Rossi shims will work Also, the muffler baffle has received
unlimited attention and inspection efforts. Why? Tests with and
w/o baffle show an average of 1000 rpm drop off with no baffle. So let the poor saps run w/o and quit worring about it. Any
comments Voodoo Doctor??
Old 05-29-2002, 11:49 PM
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bl10
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Default F.Y.I. APRA Rules Enforcement At Whittier

The inside of the muffler, including the baffle, can be modified to increase power. Thus the reason for easy inspection.


Barry
Old 05-30-2002, 01:21 AM
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MDP
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Default F.Y.I. APRA Rules Enforcement At Whittier

I am inclined to agree with LEFTY.......A few years back it was OK to remove the baffles in APRA, and cut the Super Tiger GS 40 exhaust stackes, or maybe it was OK because nobody cared. There was a rule change, and the baffels had to be in, and no cutting of the exhaust stacks. Maybe Jim remembers. I recall my engine ran better with the baffle in, with a more consistant needle, and didn't hurt the power, so even when it was OK to take them out, I left them in. I am sticking my neck out now :drowning:, because I don't remember for sure, but I don't think it tached any better without the baffle. The only higher tach reading I saw was, drilling out the exhaust stinger bigger, some guys got caught drilling holes in the bottom of the muffler to relieve exhaust pressure for a gain, and some went so far as to leave the tail cone of the muffler loose to relieve some more pressure , easy to spot because they would spin around. Most of these guys went lean before the tenth lap. The carb bore diameter, is designed to work the best with a certain stock muffler stinger hole size. The TT's are maxed out. Releiving muffler pressure, ment not enough muffler pressure to the tank, which ment having to be rich for the first few laps, and possibly over lean for the last few, not the best setup..........RIGHT LEFTY ? Any one out there reading this know "FOR SURE" what TT's tach with & without the baffle ? Especially with a unload prop at say 20K RPM ?
Old 05-30-2002, 02:40 AM
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PylonWorld
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Default F.Y.I. APRA Rules Enforcement At Whittier

Originally posted by Lefty
... What next magic man, filling in the TT motor mount holes for more speed? ...
Going off topic a little, but ...

That's an interesting point. Do the rules require that Quickie engines even have mounting lugs? I'll have to check that one out. I know Dub is a major test stand proponent (and so am I now), but if lugs aren't required, Dub (or Henry) could knock them right off on the 428 engines. But then I would need a Back Mount Engine Adapter for my www.pspmfg.com test stand.

I just looked at the rules and I can't find a requirement that engines must have side mounting lugs ... They may be necessary from a strength standpoint, though.
Old 05-30-2002, 03:03 AM
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Default RPM Reading TT Pro .40

Mike,

From my own Tach reading of the TT Pro .40, I got 17,200 RPM without the baffle and 16,900 with the baffle on the ground. However, in flight test with same plane (Predator), same fuel, same day and same time, same prop, the engine with the baffle seem to unload better and seem to out perform the one without the baffle by about 10mph in speed (at least that what I think from own observation). Plus, the needle setting is more consistant with the baffle in it.

Sam S.
Old 05-30-2002, 10:10 AM
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Default F.Y.I. APRA Rules Enforcement At Whittier

I do not think we will see the end of mounting lugs. The lugs are used as tooling points for the machining of the crankcase. Where else could it be held while all the boring takes place. If the manufacturer removes the lugs (Why would they) then OK, if an individual removes them the engine is no longer legal.

Ed S
Old 05-30-2002, 01:36 PM
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Default F.Y.I. APRA Rules Enforcement At Whittier

YEP !.....Right Ed...Don missed the point Lefty was making. Lefty was KIDDING about filling in the four lug mounting holes as a speed secret, to make the plane faster. I like the idea of chrome plated head bolts. Now there's a speed secret. :bananahea
Old 05-30-2002, 02:22 PM
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Default F.Y.I. APRA Rules Enforcement At Whittier

Mike,

I got the joke about filling in the mounting lugs. Even though Lefty was kidding about the mounting lugs, filling them with adhesive would probably not be considered a modification of the engine, since it would not result in affecting engine performance. But the airframe rules say "No cowling or streamlining of the engine is permitted", so that would probably preclude filling in the holes.

Ed,

>> The lugs are used as tooling points for the machining of the crankcase. Where else could it be held while all the boring takes place.

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