Van's Air Force
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Extended Hub
- Thread starter ww2planes
- Start date
frankh
Well Known Member
I believe its 2 and 5/8ths
longer.
I say this cus the Sam James cowl uses either an extended hub prop OR a compact hub plus a 2 5/8ths extension.
I have a 2.25" extension and trimmed the cowl to fit.
ut I can't see how you would use it with a standard Vans cowl as the spinner would be out further.
Now you could buy a James cowl....MUCH better looking IMHO....
Frank
longer.
I say this cus the Sam James cowl uses either an extended hub prop OR a compact hub plus a 2 5/8ths extension.
I have a 2.25" extension and trimmed the cowl to fit.
ut I can't see how you would use it with a standard Vans cowl as the spinner would be out further.
Now you could buy a James cowl....MUCH better looking IMHO....
Frank
gmcjetpilot
Well Known Member
Buyer Beware
Keep in mind all extended props are NOT aerobatic, limited to 3.8g's I believe.
You need to go with a James aircraft cowl, which is longer but that 1 and 1/2 inch. The James cowl is fine and you will pickup speed with the internal plenum. Van's aircraft did make longer cowl at one time, but those days have passed about 10-15 years ago. You may find an old one, but the old Gel coat cowls are heavy and not as nice as the epoxy ones. Would not recommend getting an old cowl. If you have a long cowl than fine use it.
Just be careful penny wise pound blaa blaa. If you are NOT close to flying, a prop sitting for a few years may need a seal rebuild.
Also there can be AD's. The extended hubs (called compact hubs sometimes) actually are pretty good. I recall few if any AD's. Call Hartzell with all the numbers and they can tell you for sure. Just know what you are buying. Some of the older HC-C2YKs for example (not what you are looking at) just took a hit AD wise. Its not fatal, but it requires an extra prop inspection on the plane every 100 hours. So if buying a C2YK you would want to know what version, since the AD does not affect all hubs.
You can buy a BRAND NEW Hartzell Blended airfoil with no AD's with better performance by several mph than what you are looking at, for about $5,500. If an old prop is overhauled you may find you don't have much "meat" left on the blades. Unless you have all the data and limits you may have worn blades that are trash at next overhaul. They do wear down over time as they get dressed out.
I see prop shops selling "experimental" props for $4,000 and laugh. They have no idea we (RV'ers) get such a nice deal on the Hartzells. List is about $3,000 more than what Van sells it for.
Buyer Beware, Good Luck, suggest you keep it simple. You may go broke saving money on this cheap prop to make it work.
You did not mention the model?ww2planes said:
Keep in mind all extended props are NOT aerobatic, limited to 3.8g's I believe.
You need to go with a James aircraft cowl, which is longer but that 1 and 1/2 inch. The James cowl is fine and you will pickup speed with the internal plenum. Van's aircraft did make longer cowl at one time, but those days have passed about 10-15 years ago. You may find an old one, but the old Gel coat cowls are heavy and not as nice as the epoxy ones. Would not recommend getting an old cowl. If you have a long cowl than fine use it.
Just be careful penny wise pound blaa blaa. If you are NOT close to flying, a prop sitting for a few years may need a seal rebuild.
Also there can be AD's. The extended hubs (called compact hubs sometimes) actually are pretty good. I recall few if any AD's. Call Hartzell with all the numbers and they can tell you for sure. Just know what you are buying. Some of the older HC-C2YKs for example (not what you are looking at) just took a hit AD wise. Its not fatal, but it requires an extra prop inspection on the plane every 100 hours. So if buying a C2YK you would want to know what version, since the AD does not affect all hubs.
You can buy a BRAND NEW Hartzell Blended airfoil with no AD's with better performance by several mph than what you are looking at, for about $5,500. If an old prop is overhauled you may find you don't have much "meat" left on the blades. Unless you have all the data and limits you may have worn blades that are trash at next overhaul. They do wear down over time as they get dressed out.
I see prop shops selling "experimental" props for $4,000 and laugh. They have no idea we (RV'ers) get such a nice deal on the Hartzells. List is about $3,000 more than what Van sells it for.
Buyer Beware, Good Luck, suggest you keep it simple. You may go broke saving money on this cheap prop to make it work.
Last edited:
N941WR
Legacy Member
Vans still makes a longer cowl, I know, I've got one. Just ask for an O-235/O-290 cowl, I think it is around 3" longer, I think. I have not compared to a standard -7/-9 cowl.gmcjetpilot said:
Standing the top cowl upright and measuring from the floor to the spinner flat my cowl is 36.75 inches "tall".
gmcjetpilot
Well Known Member
Thanks
Oh good to know. Yea I did not think of that. Thanks for the info. GN941WR said:
Not the same "longer".
The O-235/O-290 cowl is not the same as the long cowl that George mentioned. The older standard cowl was for a fixed pitch prop using a 4 inch prop extension. I think the O-235/O-290 cowl is 2 inches (as installed) longer than a standard cowl.
I would be very careful purchasing an older Prop without researching AD's and or having it inspected by a prop shop.
N941WR said:
The O-235/O-290 cowl is not the same as the long cowl that George mentioned. The older standard cowl was for a fixed pitch prop using a 4 inch prop extension. I think the O-235/O-290 cowl is 2 inches (as installed) longer than a standard cowl.
I would be very careful purchasing an older Prop without researching AD's and or having it inspected by a prop shop.
Andy Duff
Active Member
Constant Speed Cowl
The fact that a 4 inch extension needed to be used on the old style "long" cowl doesn't mean that the cowl was 4 inches longer than the "new" constant speed cowl. Remember, even the standard C2Y compact hub spaces the back of the prop blade away from the mounting flange some amount.
If you have a few minutes to read, I can paraphrase a few of the old RVators I have lying around where Van wrote about designing and building the "new" constant speed cowls. The first one I have is from Sept 1987 where Van was exploring the idea of which constant speed prop to use. In that article he reviewed all the propellers available from Hartzell, and said that he was going to use a HC-M2YL-7663-6 for his O-320 powered RV-6 prototype. He talked about the bolt adapters that he needed to make, but his basic point was that this prop with the 2 9/16 extension, put the back of the blade about 4 7/8 away from the mounting flange. (would leave a gap between his current spinner and the cowl) but he figured that that prop was the best fit. He later noted that that prop was extremely rare, and wanted to redesign his cowl.
In the Sept 1988 edition, Van announced that he would be redesigning the cowl to permit the use of the "readily available" C2YK hub. This cowl would be 1 3/4 shorter than the standard cowl (the one that needs the 4 inch extension)
In the June 1989 edition, he stated that the new cowl was finally in production.
My point is, that the constant speed cowl is not all that much shorter than the old (original) cowl. It does, however, require a 13 inch spinner as opposed to the old style 12 inch diameter.
Anyway, thought you might like some of the background.
The fact that a 4 inch extension needed to be used on the old style "long" cowl doesn't mean that the cowl was 4 inches longer than the "new" constant speed cowl. Remember, even the standard C2Y compact hub spaces the back of the prop blade away from the mounting flange some amount.
If you have a few minutes to read, I can paraphrase a few of the old RVators I have lying around where Van wrote about designing and building the "new" constant speed cowls. The first one I have is from Sept 1987 where Van was exploring the idea of which constant speed prop to use. In that article he reviewed all the propellers available from Hartzell, and said that he was going to use a HC-M2YL-7663-6 for his O-320 powered RV-6 prototype. He talked about the bolt adapters that he needed to make, but his basic point was that this prop with the 2 9/16 extension, put the back of the blade about 4 7/8 away from the mounting flange. (would leave a gap between his current spinner and the cowl) but he figured that that prop was the best fit. He later noted that that prop was extremely rare, and wanted to redesign his cowl.
In the Sept 1988 edition, Van announced that he would be redesigning the cowl to permit the use of the "readily available" C2YK hub. This cowl would be 1 3/4 shorter than the standard cowl (the one that needs the 4 inch extension)
In the June 1989 edition, he stated that the new cowl was finally in production.
My point is, that the constant speed cowl is not all that much shorter than the old (original) cowl. It does, however, require a 13 inch spinner as opposed to the old style 12 inch diameter.
Anyway, thought you might like some of the background.
