|
Quote:
And I thought those British guys spelled aluminum weirdly. |
Aloominum, Aluminium, Aluminum
Well, Mike.
I was just trying to get it phonetically correct. Was I close? Pete. |
So....
what I have read it would be in my best interest to go with a Hartzell BA prop due to cost, repairability, speed? RV7 With Superior XPI0360 w/fwdsump. I am not into researching too much and the various (numerous) manufactures just gives me a headache. Like everyone else, I believe, I want to go the fastest, most economically, and less money spent. Just trying to keep working at my paying job just to be able to fly.
|
Quote:
An uncle was serious offering me a job driving one of his mail trucks instead of flying for the USAF...it was a better job, safer, had holidays off , home every night and could take the dogs out racoon hunting most every night during season. Maybe he was right. Life is life where ever you are. :) |
MT prop performance
Jim Ayers, late last fall you posted that you were going to do some flight testing of the various props. Did that happen, and if so, what were your findings.
As you may know, I built an RV-7A with an MT prop. I had a great experience with the MT prop on my 10, and in side-by-side flights with other 10's, including van's, it appeared that performance was really close to the Hartzell BA. The smoothness was really wonderful, probably helped along by the 6 cylinder engine, too. The performance on the 7A does not seem to be as close. The engine is a brand new O-360-A-1A from Van's, that was sent to Barrett for porting, balancing, flow matching, and 9:1 pistons. It dynoed at 189 HP. Here are some recent numbers, gained using the box GPS method and tracking 4 ground tracks 90 degrees apart. Altitude: 4670' Temp: 62F MP: 25.2" RPM: 2500 Fuel Flow: 12.2 gph TAS: 191 mph Altitude: 7500' Temp: 51F MP: 22.8" RPM: 2400 Fuel Flow 11.2 gph TAS: 189 mph It appears that I am about 10-15 mph slower than Van's at 75% power, and I might actually be above 75% power here (got to love the lycoming power charts!). By the way, if anyone with a Hartzell BA prop is interested in coming to Mallards Landing (GA04) some Saturday/Sunday and swapping props for a direct comparison, I am game. :) Vic |
same here....
Vic,
I'd be interested in hearing of your findings as well. I've got a 7A with a 3 blade MT prop with same questions and similar performance. http://www.vansairforce.com/communit...ead.php?t=8291 I tried tweaking but never found anything to point to other than the prop. One of these days I'm going to swap it out with a Hartzell and see if it really is the prop. Doug |
Yes, that's why I made the offer out to anyone to swap with a Hartzell BA for a day and settle it. I have many thougsands of hours in RV's, and the 7A is slower with the MT prop. I wouldn't state that here if I didn't think it was so. I've been a very avid supporter of the MT props, as I was especially satisfied with it on the RV-10. Unfortunately, both Jim Ayers and Gerd at MT are not very receptive to hearing that. Lot's of extra data is needed, supposedly. Not really. I think, but don't know for sure, that the RV-10 blades were designed for the RV-10. At least that is what Eric at MT told me when I first purchased it. I think that the blades we are using for the other Rv's may not have been specifically designed for them, and perhaps aren't quite as efficient. Mine appears to be about 10-15 knots slower than I am used to seeing at similar power settings. I'll try to get some more numbers here in the not-too-distant future and post them here. It's a little hard to set aside a couple of hours for flight testing on the week ends after having had my wife spend every week end with me since last September building it. I'm now trying to take her places on the week ends. Oh, and I get to fly, too. :)
It's not like I am really upset about it. The prop is still really smooth, and 10 knots doesn't make that much of a difference on a 2-3 hour flight. But the attitude about it really rankles me, and from the response I got from Gerd at OSH tells me he is overly sensitive to it. Vic |
Vic,
Your not upset about 10 knots?:( Man dont let Bob Axom read that!. You are right on on all points based on my experience Vic. Only a bolt on the same plane comparison with good telemetry tells the tale. Been there done that. Jamie, what do you say we take a Saturday and go bolt your prop onto Vics bird? This would be a good test bed. |
Quote:
I know that Vic sold a Hartzell prop to Steve Ashby who still has it in his house. If we don't want to swap completely we could probably just get that prop from Steve and run it down to Mallards in my truck, or Vic could come to LZU and we could swap it out there. |
Vic I think we have rousted up some troups and volunteers for you.
Lets take the planning off-line and report back the results. Ill supervise:eek: |
| All times are GMT -6. The time now is 01:41 AM. |