Van's Air Force
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New Wheel Fairings From LoPresti Fully Enclose Wheels
- Thread starter Jason P
- Start date
Interesting...
What is visible of the operating mechanism appears similar to what Jim Bede patented in 1973 (See U.S. Patent 3,750,986 - long expired of course).
You can punch in the number here to see it:
http://patft.uspto.gov/netahtml/PTO/srchnum.htm
What is visible of the operating mechanism appears similar to what Jim Bede patented in 1973 (See U.S. Patent 3,750,986 - long expired of course).
You can punch in the number here to see it:
http://patft.uspto.gov/netahtml/PTO/srchnum.htm
pierre smith
Well Known Member
Nick Jones...
....had a pair on his Cassutt in the early seventies as well. What's amazing is the fact that this little effort would cost probably 30HP if it were done by horsepower instead!
Are you listening Bob Axom?
Regards,
....had a pair on his Cassutt in the early seventies as well. What's amazing is the fact that this little effort would cost probably 30HP if it were done by horsepower instead!
Are you listening Bob Axom?
Regards,
brianwallis
VAF moderator
ah yes
I looked at these very carefully several days ago. They are hydraulic and are spring loaded OPEN..... if you lose your fluid, they will open for you. If they somehow stick....the nice young lady at the display informed me that the runway will wear through the material very quickly and you will have your wheels rolling on the ground. I'll let someone else try that particular feature. She says they will be made for the rv's in the very near future.... their landing lights were pretty nice too!
Best
Brian
I looked at these very carefully several days ago. They are hydraulic and are spring loaded OPEN..... if you lose your fluid, they will open for you. If they somehow stick....the nice young lady at the display informed me that the runway will wear through the material very quickly and you will have your wheels rolling on the ground. I'll let someone else try that particular feature. She says they will be made for the rv's in the very near future.... their landing lights were pretty nice too!
Best
Brian
grantcarruthers
Well Known Member
"7 mph on an RV-7" sounds pretty sweet for such a small mod regarding weight and complexity. Plus, it would likely reduce our fiberglass work as they'd come complete I'm guessing. I'm all in unless the price is over say $1000.
Wonder if it's a electric/hydraulic pump or a lever/mechanical pump?? How much hydraulic fluid would you have to move to operate doors like that?? Hopefully little enough to require a small mechanical pump ie:cheep light and simple (er).
Wonder if it's a electric/hydraulic pump or a lever/mechanical pump?? How much hydraulic fluid would you have to move to operate doors like that?? Hopefully little enough to require a small mechanical pump ie:cheep light and simple (er).
Kevin Horton
Well Known Member
Is that speed gain based on actual flight test data, or did it come from the marketing department?
I wonder how much they weigh.
Potentially followed quickly by the tire going flat after being cut by the shredded fiberglass from the pant that you wore through....yeah, someone else can test that....(I've already had a fault from contact with the edge of the pant...)
Paul
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I Have thought about them
I have thought about exactly the same thing but I haven't worked out a clean implementation yet - may never get there but it is certainly doable. It seems like a full enclosure would be even better than the tangent interface close fitting subfairing that I added to my old style nose wheel fairing. You can't get into thinking about this area of the airplane from a drag perspective without thinking about this. I have not done anything with the main gear fairings yet. The subfairing on the nose added considerable speed in my case. The shape at the bottom is very similar to mine except that mine has one inch of tire continuing the shape instead of extending the profile lower to cover the tire. My nosegear fairing extends well below the point where the tire expands when contact is made with the ground and the edges of the opening are almost tangent to all points of near contact between the tire and the fairing thus any contact is a rubbing interface rather than an interference interface. This condition may not be possible with the rounded cross section of the newer pressure recovery fairings but that is what I have on the mains. I have been thinking about loading up the mains with clay and using my little clay working tools from Hobby Lobby to get the shape I want and laying up fiberglass for subfairings there but there are a collection of cross country air races every few weeks now (www.sportairrace.org) and the spring landscape chores are coming alive so I'm not sure when it will happen. Here is my nosegear configuration:
Bob Axsom
I have thought about exactly the same thing but I haven't worked out a clean implementation yet - may never get there but it is certainly doable. It seems like a full enclosure would be even better than the tangent interface close fitting subfairing that I added to my old style nose wheel fairing. You can't get into thinking about this area of the airplane from a drag perspective without thinking about this. I have not done anything with the main gear fairings yet. The subfairing on the nose added considerable speed in my case. The shape at the bottom is very similar to mine except that mine has one inch of tire continuing the shape instead of extending the profile lower to cover the tire. My nosegear fairing extends well below the point where the tire expands when contact is made with the ground and the edges of the opening are almost tangent to all points of near contact between the tire and the fairing thus any contact is a rubbing interface rather than an interference interface. This condition may not be possible with the rounded cross section of the newer pressure recovery fairings but that is what I have on the mains. I have been thinking about loading up the mains with clay and using my little clay working tools from Hobby Lobby to get the shape I want and laying up fiberglass for subfairings there but there are a collection of cross country air races every few weeks now (www.sportairrace.org) and the spring landscape chores are coming alive so I'm not sure when it will happen. Here is my nosegear configuration:
Bob Axsom
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Norman CYYJ
Well Known Member
Bob have you tried to completely close the wheel pant off by using some rubber gasket material? The tire would still stick out but the gaps around the wheel would be filled. If you have did you notice any difference?
No I haven't tried the rubber seal
I e-mail communicated with Tom Martin of Ontario who has used rubber seals on his EVO Rocket. He suggested it to me as a possibility and he did it on his plane. He said it seemed to help at first but the rubber at the rear of the fairing got beatup and the advantage went away. I thought a lot about what he told me and wondered how I could use rubber seals and avoid the rear conflict damage. I visualized the rubber being jammed into the oncoming tire as it compressed and spun up causing conflict deformation on landing and not conflict with the tire when being pushed backward. The best I came up with was orienting the the rear rubber with the forward edge pointing at the center of rotation of the wheel. It just didn't seem like a good and durable configuration. I believe Tom mentioned that maybe getting a good close fit was as good an approach as any. I thought that for normal cross country flying the stock configuration is OK but instead of making a whole new fairing, maybe a close fitting subfairing just for racing would be good enough. Tom Agreed that that sounded like a reasonable approach so I applied the clay and ran the fiber glass right up to intimate contact with the tire one inch above the ground. I pulled that first layer and went through the build up and all of the detail work for the installation. At that point the the opening around the tire was the same size as the tire so there were no gaps. I had to have some clearance so I decided on a 3/16" cutback from the edge. Here is where it gets interesting. The angles of the subfairing at every point are so small relative to the tire surfaces (all around) that the actual gap is much smaller than the cutback and infact are so small that I don't think there would be a great increase if they were sealed completely. I have flown and landed the plane several times and I have removed the subfairing for inspection. I can find no evidence of any contact. If there were to be any contact it would be tangential even on the sides because of the angles of the fairing relative to the tire and the fact that the lateral deformation of the tire occurs well above the edges of the side fairing. Tom has done more work with the seals on his plane and he may be able to shed more light on their effectiveness.
Bob Axsom
I e-mail communicated with Tom Martin of Ontario who has used rubber seals on his EVO Rocket. He suggested it to me as a possibility and he did it on his plane. He said it seemed to help at first but the rubber at the rear of the fairing got beatup and the advantage went away. I thought a lot about what he told me and wondered how I could use rubber seals and avoid the rear conflict damage. I visualized the rubber being jammed into the oncoming tire as it compressed and spun up causing conflict deformation on landing and not conflict with the tire when being pushed backward. The best I came up with was orienting the the rear rubber with the forward edge pointing at the center of rotation of the wheel. It just didn't seem like a good and durable configuration. I believe Tom mentioned that maybe getting a good close fit was as good an approach as any. I thought that for normal cross country flying the stock configuration is OK but instead of making a whole new fairing, maybe a close fitting subfairing just for racing would be good enough. Tom Agreed that that sounded like a reasonable approach so I applied the clay and ran the fiber glass right up to intimate contact with the tire one inch above the ground. I pulled that first layer and went through the build up and all of the detail work for the installation. At that point the the opening around the tire was the same size as the tire so there were no gaps. I had to have some clearance so I decided on a 3/16" cutback from the edge. Here is where it gets interesting. The angles of the subfairing at every point are so small relative to the tire surfaces (all around) that the actual gap is much smaller than the cutback and infact are so small that I don't think there would be a great increase if they were sealed completely. I have flown and landed the plane several times and I have removed the subfairing for inspection. I can find no evidence of any contact. If there were to be any contact it would be tangential even on the sides because of the angles of the fairing relative to the tire and the fact that the lateral deformation of the tire occurs well above the edges of the side fairing. Tom has done more work with the seals on his plane and he may be able to shed more light on their effectiveness.
Bob Axsom
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Norman CYYJ
Well Known Member
Bob, instead of using a rubber seal at the back of the wheel how about a seal made with a brush type seal. I mention this only for races of course because a knot or two in daily flying is neither here nor there.
dpansier
Well Known Member
LoPresti wheel enclosures
I recall the price at $2800. for the A models (3 pants) and 2/3 of that for 2.
7 knots was the reported speed gain with these mounted on an "A" model RV.
I did take several detailed photos and will post when I return as I forgot the camera cable.
I recall the price at $2800. for the A models (3 pants) and 2/3 of that for 2.
7 knots was the reported speed gain with these mounted on an "A" model RV.
I did take several detailed photos and will post when I return as I forgot the camera cable.
Bede Speedpants
Looks Alot like Bede
http://www.bedecorp.com/images/pricelists/bd4_speed_pants.pdf
kj
Looks Alot like Bede
http://www.bedecorp.com/images/pricelists/bd4_speed_pants.pdf
kj
ScottSchmidt
Well Known Member
I had a friend call me when he saw these. Pretty neat idea but my comment was, it might be worth 2 mph at the most. I cannot believe 7mph.
Van's claims a 2mph difference between the 7 and 7A. That means you are going 2 mph faster if remove the whole front gear.
I agree with previous posters that I would have to see some data on this especially after seeing the price. It is also one more thing that I just don't need to go wrong, leak, or forget. If I had to place bets, I would say max 2mph increase but most likely 1 mph. Now the WOW factor sitting at an airshow is a 10! You have to love ingenuity of this market though. Still a neat idea but the cost/benefit ratio just isn't there for the weight and complexity.
What that product needs is curb feelers but have them point down. Then on landing they can open themselves up and you don't have to even thing about it.
Van's claims a 2mph difference between the 7 and 7A. That means you are going 2 mph faster if remove the whole front gear.
I agree with previous posters that I would have to see some data on this especially after seeing the price. It is also one more thing that I just don't need to go wrong, leak, or forget. If I had to place bets, I would say max 2mph increase but most likely 1 mph. Now the WOW factor sitting at an airshow is a 10! You have to love ingenuity of this market though. Still a neat idea but the cost/benefit ratio just isn't there for the weight and complexity.
What that product needs is curb feelers but have them point down. Then on landing they can open themselves up and you don't have to even thing about it.
...and replace it with a smaller, but still pretty draggy tailwheel contraption.
I think this kind of idea is a great way to improve grass/unimproved strip performance without sacrificing speed. Not convinced that it is the perfect incarnation of the concept yet. It might get some brains ticking though...
A
John Clark
Well Known Member
Hmmm...
Wonder if your insurance carrier would consider them "retractable" and raise your rates?
John Clark
RV8 N18U "Sunshine"
KSBA
Wonder if your insurance carrier would consider them "retractable" and raise your rates?
John Clark
RV8 N18U "Sunshine"
KSBA
I think 2 knots is too low
Depending on the installation of the old fairings there is a lot of speed to be gained and 7 knots is not completely unbelievable. Working with the nosewheel fairing alone I got on the order of 3 knots increase in speed. But, even when you consider a two knot increase in speed at the top end - I think that is not a trivial increase.
Bob Axsom
Depending on the installation of the old fairings there is a lot of speed to be gained and 7 knots is not completely unbelievable. Working with the nosewheel fairing alone I got on the order of 3 knots increase in speed. But, even when you consider a two knot increase in speed at the top end - I think that is not a trivial increase.
Bob Axsom
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RVbySDI
Well Known Member
just getting back to the forum.
I am just getting back to the forum after going to Sun n Fun. I also saw these at the show. I was not paying enough attention to know for sure but I do believe I was talking with LoPriesti or at least one of the engineers involved and not just a sales person. Anyway, $2800 was the quote for 3 fairings for an RV-10 or RV-7A. I asked him about the 9 and he said he had not done testing on any of the other RV's except the 10 or 7. When I told him the 7A and 9A should have identical wheels and landing gear he agreed that the 7A model should fit on the 9A and get similar results.
I asked him about actuating the mechanism. He said it is hydraulic and that you can put a lever to actuate it but he had set a limit switch up on his throttle so that when he reduced the power the switch would activate the hydraulic pump and the doors would open automatically.
My thoughts on this: Coming away from talking with him I felt that for $2800 I could buy an awful lot of fuel even at the 7 knots increase claimed (he did talk about knots and not mph when he discussed speed increases).
The complexity sounds a bit much if trying to keep the plane simple and light.
I am just getting back to the forum after going to Sun n Fun. I also saw these at the show. I was not paying enough attention to know for sure but I do believe I was talking with LoPriesti or at least one of the engineers involved and not just a sales person. Anyway, $2800 was the quote for 3 fairings for an RV-10 or RV-7A. I asked him about the 9 and he said he had not done testing on any of the other RV's except the 10 or 7. When I told him the 7A and 9A should have identical wheels and landing gear he agreed that the 7A model should fit on the 9A and get similar results.
I asked him about actuating the mechanism. He said it is hydraulic and that you can put a lever to actuate it but he had set a limit switch up on his throttle so that when he reduced the power the switch would activate the hydraulic pump and the doors would open automatically.
My thoughts on this: Coming away from talking with him I felt that for $2800 I could buy an awful lot of fuel even at the 7 knots increase claimed (he did talk about knots and not mph when he discussed speed increases).
The complexity sounds a bit much if trying to keep the plane simple and light.
System complexity and price are Turn Offs
The system complexity and cost are definitly turn offs and if you do not have the need for the absolute best speed they will surely bring you grief. There are some out there lusting for ~$10,000 Hartzell 7496 Blended airfoil blades to gain 3 kts and for them (sigh) this may be a bargain. I would give it time to establish some field history before I jumped on the bandwagon. I think I can get very close to the same performance by modifying the fairings. People with conventional gear (tail draggers) may find the door approach safer than what I have done with my nose gear fairing because of the possibility of catching the fixed downward extended fairing between the ground and the tire on a tail high landing. If LoPresti gets certification for production planes I think that will be the best market for them because those planes are so much slower and the speed gains would seem more dramatic and easier to come by. This will definitly be getting a lot of attention if they can overcome complexity and cost barriers with undeniable performance improvement. If the system is installed by experts and all you have to do is flip a switch it will not SEEM so complex - until there is a flight operation or functional failure. I will continue to do my own thing but it is going to be interesting to watch.
Bob Axsom
The system complexity and cost are definitly turn offs and if you do not have the need for the absolute best speed they will surely bring you grief. There are some out there lusting for ~$10,000 Hartzell 7496 Blended airfoil blades to gain 3 kts and for them (sigh) this may be a bargain. I would give it time to establish some field history before I jumped on the bandwagon. I think I can get very close to the same performance by modifying the fairings. People with conventional gear (tail draggers) may find the door approach safer than what I have done with my nose gear fairing because of the possibility of catching the fixed downward extended fairing between the ground and the tire on a tail high landing. If LoPresti gets certification for production planes I think that will be the best market for them because those planes are so much slower and the speed gains would seem more dramatic and easier to come by. This will definitly be getting a lot of attention if they can overcome complexity and cost barriers with undeniable performance improvement. If the system is installed by experts and all you have to do is flip a switch it will not SEEM so complex - until there is a flight operation or functional failure. I will continue to do my own thing but it is going to be interesting to watch.
Bob Axsom
dpansier
Well Known Member
LoPresti Wheel Pants
Photos of the wheel pants and front page of the expired patent.
The patent mentions a 10% speed improvement, I believe these pants were developed for the BD4.
http://img171.imageshack.us/img171/6149/dsc00845kx3.jpg
http://img258.imageshack.us/img258/1230/dsc00844ig5.jpg
http://img405.imageshack.us/img405/5408/dsc00843wp3.jpg
http://img170.imageshack.us/img170/2743/dsc00841bd8.jpg
http://img170.imageshack.us/img170/1300/us003750986qx5.jpg
Photos of the wheel pants and front page of the expired patent.
The patent mentions a 10% speed improvement, I believe these pants were developed for the BD4.
http://img171.imageshack.us/img171/6149/dsc00845kx3.jpg
http://img258.imageshack.us/img258/1230/dsc00844ig5.jpg
http://img405.imageshack.us/img405/5408/dsc00843wp3.jpg
http://img170.imageshack.us/img170/2743/dsc00841bd8.jpg
http://img170.imageshack.us/img170/1300/us003750986qx5.jpg
aparchment
Well Known Member
winter ops
I wonder what snow and ice will do to the proper functioning of these.
I wonder what snow and ice will do to the proper functioning of these.
redbeardmark
Well Known Member
V-speed?
Is there a Vle or Vfe for these things?
Is there a Vle or Vfe for these things?
