.30 engines in 2548

Bruce B · Post by **Bruce B** » Sat Oct 18, 2008 5:18 pm

I got a friend of mine that just bought a thunder tiger GP .28. after a three tank break in we mounted it on his jk aerotech corsair.with the mas 10x4 and 15% wildcat fuel we got 13,400. it is still pretty tight so maybe a little more rpm later. runs very well and has a very smooth throttle transition from low speed.removed the baffle from the muffler after a few tanks and got absolutley nothing from it,still 13,400. even though it wont turn 14,500 it should still be competitave with a good pilot. it is a shame we cant use this $60.00 motor (or the magnum)to compete.cost is a big factor in this hobby, and the $35 difference is why he bought this motor instead of the fx. it is way better than the .25la he replaced, at about the same price.

crash_out · Post by **crash_out** » Sat Oct 18, 2008 6:39 pm

That again was a point of my argument. With a $35 price difference,you can buy 3 TT or Mags for the price of 2 FX's. It certainly makes getting into it cheaper. You may be starting off 1000 rpm's lower than an FX, but at least you can compete. With an APC 10x3, you might could make 14,500.

I flew my first ever round of SSC with a Magnum .15 that could only turn 16,200rpm, and pulled off a 4 cut round. That's good no matter how you look at it.

Hat Trick · Post by **Hat Trick** » Sun Oct 19, 2008 4:30 pm

I think if you build scale planes and show up at a contest and meet the RPM limit everyone will be very happy you showed up and not say a word!

Bruce B · Post by **Bruce B** » Sun Oct 19, 2008 9:31 pm

I think that something could be done to get some support for this rule change.Whatever we can do to get more people flying would be a step in the right direction.We didnt even fly 2548 at the last meet because there were only 3 or 4 pilots for the class. I think we had 9 in ssc.this probably had nothing to do with bigger motors but if it was a little cheaper to get into then just maybe one or two of the spectators might get interested enough to try it. just my opinion

crash_out · Post by **crash_out** » Sun Oct 19, 2008 9:40 pm

I agree with you, Mike. If I were hosting an event, and someone showed up with the Mag or TT (or anything, for that matter)that met the class limits, I'd let them fly.

Post by **boiler** » Mon Oct 20, 2008 10:32 am

Any one of you are welcome to submit a rule change proposal to allow up to a .30 engine in 2548 which would be consistant with the AMA scale class. Why not do that and get a vote rather than hashing it over here?

draftman1 · Post by **draftman1** » Mon Oct 20, 2008 10:50 am

Im for the change also. it just seemed dumb to have different engine sizes in a class that was almost the same. I know the realistic factor was a big part of it but the cost of the 25fx has gotten to high for people to try it. I agree with boiler. get it together and get a vote on it

Bruce B · Post by **Bruce B** » Mon Oct 20, 2008 7:18 pm

thanks for the effort again guys. i am a newbie to this and had no idea how to submit a proposal. i hope this will open up the class a little more

crash_out · Post by **crash_out** » Tue Oct 21, 2008 5:16 am

I submitted the proposal in the rules discussion area, so everyone check it out.

sgilkey · Post by **sgilkey** » Tue Oct 21, 2008 7:36 am

I'd really suggest commonizing the proposal with the Limited B rules (which allow up to .29 and otherwise are identical to 2548 regarding carb, muffler, etc). This would make the two classes the same in terms of powerplant/prop, which they essentially are already, except that folks can use common and inexpensive .28 type engines in Limited, where they have not shown ANY advantage in three years of experience.

Serg · Post by **Serg** » Wed Oct 22, 2008 9:09 pm

.28 engines are chieep because they a not so good engine.

If you allowed 0.28 somebody will build really good engine.

p.s. if prop/RPM ratio is written in rules there is no reason for any other limitation.

Propeller parameter plus maximum RPM allowed is equal power limit.

Post by **boiler** » Thu Oct 23, 2008 4:00 pm

I posted here but moved it to the members only forum where rules discussions belong.

Bruce B · Post by **Bruce B** » Sun Oct 26, 2008 10:49 am

Tried some 20% in the thunder tiger gp .28. got 13,900 with a 10x4. gonna try a 10x3 when i get to the lhs.Just thought someone might want to know.

Post by **boiler** » Sun Oct 26, 2008 3:47 pm

The 10x3 isn't a MAS but the harder grey APC.

sgilkey · Post by **sgilkey** » Mon Oct 27, 2008 8:23 am

Check the head shim on the GP28. I haven't had one, but often on other engines TT has a very thick head shim and you can get a bit more power by putting in a thinner shim. 13,900 is respectable, I think anything 14k or higher and you will be in fully competitive in LimB or 2548.