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#1
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My club is about to acquire a 250 HP Pawnee with no muffler and a 7 ft
climb pitch prop. We are anticipating some noise issues. I have seen Pawnees in the UK with mufflers and four bladed (Hoffmann?) props and which were eerily quiet. Anyone know what these mods cost, in performance and money? Richard Kellerman |
#2
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On Jan 24, 11:42 am, wrote:
My club is about to acquire a 250 HP Pawnee with no muffler and a 7 ft climb pitch prop. We are anticipating some noise issues. I have seen Pawnees in the UK with mufflers and four bladed (Hoffmann?) props and which were eerily quiet. Anyone know what these mods cost, in performance and money? Richard Kellerman Call Mile High Gliding. Not sure if there's a 250hp pitch http://www.milehighgliding.com/common/propposter.doc |
#3
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Thanks, Frank.
Clicking our thumbnail Ad at the Lower Right Hand corner of www.ssa.org will take you directly to our product information page. We hold the FAA STC and dealer authorization from Hoffmann Propeller GmbH & Co. KG. Mile High Gliding, Inc. Boulder, CO |
#4
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On 24 Jan, 17:42, wrote:
My club is about to acquire a 250 HP Pawnee with no muffler and a 7 ft climb pitch prop. We are anticipating some noise issues. I have seen Pawnees in the UK with mufflers and four bladed (Hoffmann?) props and which were eerily quiet. Anyone know what these mods cost, in performance and money? Borders GC has a small Pawnee which came with 150bhp engine, 4-bladed prop and silencer. Yes, stunningly quiet - you could barely hear it as it passed with a tow. The downside was that it couldn't pull the skin off a rice pudding - fine for single seaters but could be a little worrying with two seaters. It later acquired a two bladed prop and 160bhp (no STC for the full 180bhp in the UK) and lost the silencer. Significantly better, but still not stunning for two-seaters. And I do think the BGA should have acquired it and kept it hushed for use at sites thinking of aerotowing and needing local permission. I had a tow behind a Rotax Falke earlier this month. That was about the same as the hushed Pawnee. Ian |
#5
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![]() "Ian" wrote in message ... On 24 Jan, 17:42, wrote: My club is about to acquire a 250 HP Pawnee with no muffler and a 7 ft climb pitch prop. We are anticipating some noise issues. I have seen Pawnees in the UK with mufflers and four bladed (Hoffmann?) props and which were eerily quiet. Anyone know what these mods cost, in performance and money? Borders GC has a small Pawnee which came with 150bhp engine, 4-bladed prop and silencer. Yes, stunningly quiet - you could barely hear it as it passed with a tow. The downside was that it couldn't pull the skin off a rice pudding - fine for single seaters but could be a little worrying with two seaters. It later acquired a two bladed prop and 160bhp (no STC for the full 180bhp in the UK) and lost the silencer. Significantly better, but still not stunning for two-seaters. And I do think the BGA should have acquired it and kept it hushed for use at sites thinking of aerotowing and needing local permission. I had a tow behind a Rotax Falke earlier this month. That was about the same as the hushed Pawnee. Ian Well, just as a counterpoint. The soaring Society of Boulder, CO operates a 235HP Pawnee with the 4-blade Hoffmann prop and mufflers and it is very quiet. However, it tows heavy 2-seaters just fine with density altitudes of well over 10,000 feet at takeoff. Tows frequently reach over 12,000 feet MSL. SSB also operates a 180HP Supercub which also tows well though not quite like the Pawnee. I think towing with a touring motorglider would not be a good idea at this altitude unless somehow the 80HP Rotax could be replaced with say, 135HP. Bill Daniels Bill Daniels |
#6
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that's the difference between 150-160-180HP and 235-250HP
We towed with a 180HP Scout, not good out here in the summer 100F plus temps at a field elevation of 2800MSL. 250HP Pawnee is much nicer, especially with a heavy Janus C with two up in tow. Tow a few 1-26s or L-33s, don't even notice them, even the 2-33, and then latch onto the Janus... you know you've hooked onto some MASS behind you. We are in the middle of the desert, we run 250HP on straight pipes and standard prop.. noise is not an issue. BT "Ian" wrote in message ... On 24 Jan, 17:42, wrote: My club is about to acquire a 250 HP Pawnee with no muffler and a 7 ft climb pitch prop. We are anticipating some noise issues. I have seen Pawnees in the UK with mufflers and four bladed (Hoffmann?) props and which were eerily quiet. Anyone know what these mods cost, in performance and money? Borders GC has a small Pawnee which came with 150bhp engine, 4-bladed prop and silencer. Yes, stunningly quiet - you could barely hear it as it passed with a tow. The downside was that it couldn't pull the skin off a rice pudding - fine for single seaters but could be a little worrying with two seaters. It later acquired a two bladed prop and 160bhp (no STC for the full 180bhp in the UK) and lost the silencer. Significantly better, but still not stunning for two-seaters. And I do think the BGA should have acquired it and kept it hushed for use at sites thinking of aerotowing and needing local permission. I had a tow behind a Rotax Falke earlier this month. That was about the same as the hushed Pawnee. Ian |
#7
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The Black Mountains Gliding Club, Wales, UK have been
operating a 235 pawnee with a hoffman 4 blade prop and gozzmogoli muffler for at least 15 years that i know of. I seem to remember someone saying it lost a few HP, but it will regularly haul a k21, Duo discus, open Jantar, Nimbus 2 off a 350 yard downhill sloping grass field as long as the ground is not to wet The field is 900ft amsl www.blackmountainsgliding.co.uk/ email the club, they should be able to put you in touch with someone with some more information, I dont do things with engines Pete At 17:48 24 January 2008, wrote: My club is about to acquire a 250 HP Pawnee with no muffler and a 7 ft climb pitch prop. We are anticipating some noise issues. I have seen Pawnees in the UK with mufflers and four bladed (Hoffmann?) props and which were eerily quiet. Anyone know what these mods cost, in performance and money? Richard Kellerman |
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