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Author Topic: How much is too much?  (Read 1404 times)

Offline Bobs your Uncle

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How much is too much?
« on: October 04, 2017, 10:43:15 AM »
I am just finishing up a lightweight 34oz (with 8 oz engine + 1/4 oz tongue muffler) 480 sq inch flapped profile plane and am ruminating about fitting an LA 46 in place of an LA 25.

Is the LA 46 too much power? Can an LA 46 run successfully with a smaller prop than the standard 12.25 x 3.75 APC? (to allow for the shorter landing gear).









« Last Edit: October 04, 2017, 01:10:23 PM by Bobs your Uncle »


Offline Steve Helmick

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Re: How much is too much?
« Reply #1 on: October 04, 2017, 01:30:58 PM »
1) Pat Johnston had a light '57 Nobler with a .25FP and liked it. With a 10" prop, IIRC. If your .25LA is as strong as a .25FP, then it should work well.

2) Tim Wescott uses an 11 x 4.5 TT prop on his .46LA. Yes, hard to get, but it shows what is possible. Zoot Zoomer was supposed to have CF copies of the 11 x 4.5 TT prop available this year...I'll axe him Saturday. The 11.5 x 4 APC is a fine prop on the .46LA, and is my "standard". A few people do seem to like the 12.25 x 3.75 APC, but not everybody. I think they're too much load. I'd try a 12 x 4 Xoar if I had a handy source...yeah, Tower Hobby sells them, but no LHS that I know of.  S?P Steve 
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Offline phil c

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Re: How much is too much?
« Reply #2 on: October 04, 2017, 02:47:59 PM »
It really is more a matter of when is the engine too big for the plane-
If the prop won't clear the ground for take off and landing
When the engine, muffler, and tail weigh make the plane too heavy to fly well
When the prop is so big and heavy you can't control it in turns of a sharp radius


I got a Brodak original Smoothie kit that turned out too light to balance with a Fox or a Brodak 40.  The LA 40 or 46 added enough weight for balance and it still weighs about 46 oz.  That is just fine for the 540 or so squares.  It flies pretty well with a Master Airscrew 10in 3 blade prop.

I'm pretty sure putting on one of the APC 11in or better props would make it do weird things.
phil Cartier

Offline Matt Spencer

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Re: How much is too much?
« Reply #3 on: October 04, 2017, 07:52:34 PM »
Yes , too much prop[ can get rather embarrasing . :-[

If it were twice as big as the plane , the plane would end up being ' the propellor ' .  :-X :( %^@

Online Arlan McKee

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Re: How much is too much?
« Reply #4 on: October 04, 2017, 08:52:22 PM »
I have had a LA46 in a Nobler for a few years running a 10 5/8 x 4 carbon prop that Steve Wilk sells. With a small os venturi it runs at about 10,100 on the ground and burns 3oz for the pattern.

Extremely versatile engine.

Arlan

Online Motorman

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Re: How much is too much?
« Reply #5 on: October 04, 2017, 09:27:33 PM »
I have a Brodak 40 on a Banshee and I have to tame it down with prop. Still cuts through the wind like nobodies business. Your plane is smaller and the LA46 is allot more power. There's an FP40 for sale in the classifieds you might want to look at.

MM
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Offline Balsa Butcher

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Re: How much is too much?
« Reply #6 on: October 05, 2017, 10:29:10 AM »
Awwww, forget about the LA-46. Does not sound like a good fit for your airplane. Use one of the Aero Tiger 36's you have stashed away. Easier retro-fit, similar weight, less vibration with more consistent power (IMHO). They work well with the APC 10.5 x 4.5" so no ground clearance issues. Just be sure to fit a 4.5 ounce tank and use 5% nitro. Still a lot of engine for that size of airplane but you can increase line length to adjust lap times if necessary.  8)
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Offline Bobs your Uncle

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Re: How much is too much?
« Reply #7 on: October 06, 2017, 09:43:47 PM »
Thanks for your ideas, the plane has come out even lighter at 30oz with an 8.5 oz engine, so I am going with a 25 for now.

Offline Mike Scholtes

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Re: How much is too much?
« Reply #8 on: October 06, 2017, 09:52:17 PM »
I have a pure BBSU FP20 that I borrowed from ... someone. Would you like to have it? Could deliver tomorrow.

Offline Bobs your Uncle

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Re: How much is too much?
« Reply #9 on: October 06, 2017, 10:04:28 PM »
I have a pure BBSU FP20 that I borrowed from ... someone. Would you like to have it? Could deliver tomorrow.

BBSU? or maybe BBTU?

I don't use Brett Buck tuned engines any more as fame is clearly going to
his head about his tuning method.

If god had intended engines to give perfect stunt runs out of the box he wouldn't have given us dremel tools and head gaskets.










« Last Edit: October 07, 2017, 08:11:21 AM by Bobs your Uncle »

Offline Brett Buck

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Re: How much is too much?
« Reply #10 on: October 06, 2017, 10:55:18 PM »

If god had intended engines to give perfect stunt runs out of the box he wouldn't have given us dremel tools.

    The existence of head gaskets and Dremel tools is God's way of punishing hubris.

     Brett

Offline Mike Scholtes

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Re: How much is too much?
« Reply #11 on: October 07, 2017, 08:53:29 AM »
"BBSU" stands for "Before Being Screwed Up" by application of Dremel tools and head gaskets, a relative virgin as it were, a pre-hubris engine.

Offline Brett Buck

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Re: How much is too much?
« Reply #12 on: October 07, 2017, 11:12:13 AM »
"BBSU" stands for "Before Being Screwed Up" by application of Dremel tools and head gaskets, a relative virgin as it were, a pre-hubris engine.

   I am going to write a book entitled "How to get really good stunt runs by drilling holes in your engine". It's a sequel to my earlier best-seller, "How Magic has improved the lot of the human race over the last 2000 years" .

    Here are the Chapters I have so far

  • 1953 was the best year ever
  • Who the hell won that war, anyway?
  • How to evaluate 7 Iron Curtain Slag Motors in an afternoon
  • If 0.003" is good, 0.030" is 10X better
  • The varied uses of Dremel cut-off wheels
  • You can never have enough power
  • Use the big venturi to Get More Power
  • Torque Flies Airplanes
    • Power is not real and eggheads just made it up
    • Long stroke stump-pullers (like a '49 Ford which is way faster than a Camry even though it had 1/4 the power and weighs 1000 lbs more)
    • Heavier Pistons for more torque
    • All the important principles of physics you learn while BSing your high school car buddies
    • Why bigger props are always better because they give you more static thrust
  • Nothing important happened in 1986
  • Nothing important happened in 1990-1994 (inclusive) and why you should not pay any attention to it
  • Why experts are so sharp that they don't need good engine runs
  • How to succeed in a competitive marketplace
    • Why putting more American Flags on the box is more important than quality control or metallurgy
    • It was right in 1949 and nothing of consequence has happened since then

  • Judge bias against mufflers and wood props and what you can do about it
  • Excuses mean never having to say you are sorry


   Brett
« Last Edit: October 07, 2017, 11:29:13 AM by Brett Buck »

Online dennis lipsett

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Re: How much is too much?
« Reply #13 on: October 07, 2017, 03:24:50 PM »
◦Why putting more American Flags on the box is more important than quality control or metallurgy

Poor Duke, even departed he is still getting razzed. Are you criticizing poor Duke's buy American campaign with buy American and flags on the box, Hummmmm.
He couldn't help it that quality control cost more than the engine. Go easy on him

Offline Brett Buck

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Re: How much is too much?
« Reply #14 on: October 07, 2017, 04:22:23 PM »
◦Why putting more American Flags on the box is more important than quality control or metallurgy

Poor Duke, even departed he is still getting razzed. Are you criticizing poor Duke's buy American campaign with buy American and flags on the box, Hummmmm.
He couldn't help it that quality control cost more than the engine. Go easy on him

They could have tried to compete, there were clear capabilities to change -  but took the bad-mouthing "jap junk" approach. Letting the market decide is even more American than the flag.

    This is independent of "Duke" and if someone expects to make him a sympathetic figure, you can look elsewhere for forgiveness.

     Brett

Offline Peter Nevai

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Re: How much is too much?
« Reply #15 on: December 06, 2017, 05:19:31 PM »
"They could have tried to compete, there were clear capabilities to change -  but took the bad-mouthing "jap junk" approach. Letting the market decide is even more American than the flag."

Pretty much Harley Davidson MC's  attitude back in the early 80's As a response to the appearance of the Kawasaki Z1 and Honda CB750, they hit American shores far cheaper, more reliable and higher performing than the biggest and baddest model Harley had. Back in those days your average Harley had of 50 / 50 chance of not starting, had acceleration slightly better than a average tree sloth, vibrated so bad you had to have your teeth fillings welded in place and would leak the contents of it's crankcase all over your garage floor if you sneezed too hard.

It took an executive order from the then President of the United States by imposing an import tariff  increase of 10 X over the existing rates from 4.4% to 49.4% of unit price to save the company from being shut down. Over the ensuing years their product caught up to modern day technology
Words Spoken by the first human to set foot on Mars... "Now What?"

Offline GERALD WIMMER

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Re: How much is too much?
« Reply #16 on: December 06, 2017, 06:02:24 PM »
"They could have tried to compete, there were clear capabilities to change -  but took the bad-mouthing "jap junk" approach. Letting the market decide is even more American than the flag."

Pretty much Harley Davidson MC's  attitude back in the early 80's As a response to the appearance of the Kawasaki Z1 and Honda CB750, they hit American shores far cheaper, more reliable and higher performing than the biggest and baddest model Harley had. Back in those days your average Harley had of 50 / 50 chance of not starting, had acceleration slightly better than a average tree sloth, vibrated so bad you had to have your teeth fillings welded in place and would leak the contents of it's crankcase all over your garage floor if you sneezed too hard.

It took an executive order from the then President of the United States by imposing an import tariff  increase of 10 X over the existing rates from 4.4% to 49.4% of unit price to save the company from being shut down. Over the ensuing years their product caught up to modern day technology

Hello Well I took it hook line and sinker down here in little old New Zealand and bought lots of those Fox 'flag' engines and GM products Like my 1960 Chevy a C10 and 2 Suburbans and my wife and I Oldsmobile's including a 67 and 76 Cutlass. Why you ask? it was so much better then either local made or British stuff we were so used to here in NZ. Harley's still rule if your a Red neck here too  ;)

Offline Brett Buck

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Re: How much is too much?
« Reply #17 on: December 06, 2017, 06:11:45 PM »
"They could have tried to compete, there were clear capabilities to change -  but took the bad-mouthing "jap junk" approach. Letting the market decide is even more American than the flag."

Pretty much Harley Davidson MC's  attitude back in the early 80's As a response to the appearance of the Kawasaki Z1 and Honda CB750, they hit American shores far cheaper, more reliable and higher performing than the biggest and baddest model Harley had.

   Yes, exactly.

    I found it a minor tragedy that Fox took their tack, because I think there is no reason at all that they couldn't have successfully competed - they just had to try. I don't know what they did in other areas, but they went around demonstrating engines and asking for input - and then ignored it or argued with people. This was long after Duke was gone, and I doubt that Duke's "legal issues" had any real bearing on the success.

     A lot of the Fox engines would have been fine for RC sport fliers with very minor improvements, but the "curb appeal" compared to OS, ST, etc, was terrible, and the other manufacturers kept improving. Take even a lowly 46LA, the cheapest of the cheap sport engines, back to 1975, and it would be like an alien artifact. Take a Fox Eagle 60 CL back to 1975, and it would even draw notice.

      Brett


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