Jgregp7372
I'm New Here
Hey guys, I have 74" Hartzell props for my RV4. I want to extend my gear struts from standard to long-legs. Is the something I'll have to cobble together or can I buy a kit?
Greg
Greg
Van's Air Force
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Longer legs for my RV4
- Thread starter Jgregp7372
- Start date
I'm curious about this issue because I have heard that the angle defined by the main gear to tail makes A-models land a little slower, and hypothetically an RV-9 with very tall gear might be a better backcountry platform.
andoman
Well Known Member
You would have to start with a call to Van’s since the -4 kit is history.
You’ll need a new mount, gear legs, and then redo all the associated fiberglass work.
I have a short gear -4 that had a 72” prop when I got it. The local prop shop took it down to 70” and I’m comfortable with the prop clearance. But I’ve only operated her on pavement.
IMHO the short gear are fine for landing distance. In the 3 point attitude there is still a little flying speed. If I need to stop short l’ll I roll the tailwheel on first. The mains will stick and I can get right on the brakes.
In the end, shortening the prop is cheaper and much easier than lengthening the gear.
You’ll need a new mount, gear legs, and then redo all the associated fiberglass work.
I have a short gear -4 that had a 72” prop when I got it. The local prop shop took it down to 70” and I’m comfortable with the prop clearance. But I’ve only operated her on pavement.
IMHO the short gear are fine for landing distance. In the 3 point attitude there is still a little flying speed. If I need to stop short l’ll I roll the tailwheel on first. The mains will stick and I can get right on the brakes.
In the end, shortening the prop is cheaper and much easier than lengthening the gear.
FlyingDutchman257
Active Member
He needs the legs as well, plus the new fairings, the old ones will be short. Roughly another 2 to 3K on top....
Larry DeCamp
Well Known Member
Why not a 3 blade prop ?
This kit comes with the longer match drilled legs. U-415 in the kit contents are the legs.
Beginning to make economical sense. $4K plus shipping and tax! Then add longer leg fairings and intersection fairings.
Having said that, I had a 76" prop on my long legged RV-4 and was comfortable with wheel landings (perhaps with tail somewhat low).
Never measured it -- what is the difference from prop center to ground, short vs long legs?
Flying EMT
Active Member
Just some numbers on my 1993 short gear RV-4 with a 72" constant speed Hartzell on 500-5 tires: 51 1/2" center of spinner to ground. 14 1/2" prop clearance in three point. 6" prop clearance with level fuselage. I wheel land 90% of the time. YMMV Ben
I had to switch to long legs, Vans will send new ones but i also had to order new leg fairings and i had to modify my wheel pants also to fit
Interesting. So you did not need a new engine mount?
74" props are for A models. 72" props are for TD models. RV-4 with short gear should be using a 72" prop. I would take it off and send to a prop shop for shortening if its the 7666 blade model. Don't have experience with 7497 (blended airfoil) prop getting that short but from the Hartzell list it says they should be 72" (74 is blade length and the -2 is how much it gets clipped from original length). I've had 7666-4 blades on my -6's and that is fine.
So if you get your blades clipped 1" each (2" total length reduction) and do 380 tires, you get about 3-4 more inches of clearance. And that is probably the cheapest and least intrusive route with the lowest amount of downtime to your bird.
So if you get your blades clipped 1" each (2" total length reduction) and do 380 tires, you get about 3-4 more inches of clearance. And that is probably the cheapest and least intrusive route with the lowest amount of downtime to your bird.
FlyingDutchman257
Active Member
The 7497 blades come as 74" or 7497-2 for the 72" prop. Both are available new through Vans. You will find the 7497 in 74" on some factory builds(certified), haven't come across the 72" variety as certified props. According TCDS, the 74" has a minimum diameter of 72". This creates the impression that they can be clipped by a propshop and are still within serviceable limits.
Does your friend need an engine mount, conical, with the standard legs?
