Question for the F1 Boss

Hey Boss,

My F1 has Grove 56-1A wheels AND brakes. The dual pistons are 1 1/4" dia and the calipers spec out new at .313" (5/16')

Groves lists the 57-1A as the same wheel. The calipers are the same body but have 1 7/16" dual pistons and a 3/8" disc. Supposedly they will fit under the pants.

If I run the power up on a max performance take off on a short field, the smaller original brakes are marginal at best and the beast is moving before brake release. I get about 50 hours out of a set of Rapco pads. Same pads with either caliper set. My question is do the larger 1.4375" pistons and the 3/8" discs fit in the pants and have you or anybody tried these?

I have redone the brakes enough times it is time to replace the discs, so it is not a big expense to try the HD calipers AND discs, if they will fit and work. The larger pistons should result in 1.32 times the brake holding force or a 40% reduction in pedal force for the same braking action. I just got 300 hours (on asphalt) out of my last set of tires after I tweaked the shims and alignment. I am happy with tire life.

Great ship overall. You should really bring back the QB!
Thanks for your thoughts.

New Question

Were any F1 kits supplied with or built with the Groves 57-1A wheel / 57-124 Kit? ( with 32-4A caliper and 018-003 Disc)

std F1 equip

The F1 came with the 56-1 wheel, 31-3M caliper, and 5/16" thick discs. This setup will ALMOST hold the ship during a full power run-up, and I guess the prop folks would like it if I supplied a brake that did hold the ship.

Static thrust is 1600-1800lbs, so even if the brakes hold, my bet is the tires will slide.

I would think that the bigger parts might fit, but be prepared to put a speed bump where the caliper might touch the wheelpant. The thicker disc will absorb more heat too, if that helps.

Looking at how long your pads DON'T last, you must be operating off 1200' pavement? Or, you are using a bit of extra energy (excess speed) on final? A high obstacle at the fence line? For comparison, I have 350hrs on my bird, and the pads are about 50% degraded; discs are fine. I operate off 2500 sod, and use about 2/3 of that if I am less than attentive on final (Evo wing). If need arises, I can get down and stopped on 300' with 15kt wind - my guess is you can duplicate that if you use 55kt as your approach speed (with appropriate power, of course).

So, I am saying that maybe your approach needs some tweaking before you put brakes on that can more easily put your prop out of service...an AOA would help there too.

Does any of this help?

Carry on!
Mark

F1Boss said:

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Static thrust is 1600-1800lbs, so even if the brakes hold, my bet is the tires will slide.:eek

Mark

Click to expand...

WOW, the IO360-200hp with the Hartzell composite blade (super good) is only about 950 lbs static. Surely, three blades will be better, but nearly 2X - that is a lot.

Not saying' it ain't so, just wondering what technical factors yield such a number.

Thanks Mark,

So If I run a small header tank to feed in a vertical nose up attitude with 1600 to 1800 lbs thrust I should be able to accelerate straight up if I keep my take off of weight below 1500lbs.

I vaguely recall published static thrust numbers for C182 s and C 185's with 300 hp Continentals and 3 blade vs 2 blade both around 1000 to 1100 lb range.

http://www.pponk.com/HTML PAGES/propellers.html

I would however, really like to fly an F1 that has 1800 lbs of pull !

Yes, that does help me with the original parts as mine evidently is. Yes I do use my brakes. Not always, but most of the time. Mine turns into a rock at 52kts , so 55kts might be a bit sporty for my comfort over the fence. If I have nice grass to round out on, 60kts works good on a steep approach with the sport wing. Mine is a touch heavy with inverted oil. I seem to have quite a few 20 -30 kt xwind take off and landings where I fly to and from. Good thing the F1 has lots of surplus rudder available.

I think I will try a set of the 3/8 thick discs as it is time to replace my originals.