Retractable RV-4 - Page 4

gmcjetpilot · #31 10-31-2019, 06:33 PM

Quote:

Originally Posted by Capt

Would be sweet but doubt it's got any useful load?

Useful load or max gross is what ever you (the builder) calls it... Experimental. Not saying that is OK, just I have seen arbitrary increase in weights before. These are no longer RV's due to the extensive modification. Not disagreeing but I bet you will find all these planes have higher magical gross weights.

gmcjetpilot · #32 10-31-2019, 06:42 PM

Quote:

Originally Posted by skylor

Dave Anders does not have a stock air frame.

Skylor

What do you mean by stock. I am no Dave Anders expert but met him once and followed all his work for a long time. First the plane is impeccably built. Air frame has custom cowl, cowl inlets, induction scoop, gear leg fairings, wheel pants, turtle deck mod, wing tips.... and every detail is tweaked for min drag. The basic structure however is stock as far as I know.

Firewall forward it's a masterpiece of engine technology, electronic fuel injection and ignition, tuned exhaust, tuned induction plenums and runners, custom engine build and min drag cooling aerodynamics. Not stock. It is a very light plane (dispute angle valve Lyc). This is just the bigger stuff. A lot of speed and efficiency can be had by many fine details.

skylor · #33 10-31-2019, 08:15 PM

Quote:

Originally Posted by gmcjetpilot

What do you mean by stock. I am no Dave Anders expert but met him once and followed all his work for a long time. First the plane is impeccably built. Air frame has custom cowl, cowl inlets, induction scoop, gear leg fairings, wheel pants, turtle deck mod, wing tips.... and every detail is tweaked for min drag. The basic structure however is stock as far as I know.

Firewall forward it's a masterpiece of engine technology, electronic fuel injection and ignition, tuned exhaust, tuned induction plenums and runners, custom engine build and min drag cooling aerodynamics. Not stock. It is a very light plane (dispute angle valve Lyc). This is just the bigger stuff. A lot of speed and efficiency can be had by many fine details.

For starters, it has a counter-balanced rudder which is not stock on -4's. In addition, his fuselage is a fastback which increases stiffness of the tail moment appreciably. I'm sure there are probably other mods that I'm not aware of but these are the two that stood out when I looked at his plane a few years ago.

Skylor

Saber25 · #34 10-31-2019, 08:33 PM

The RV4 retract has a similar profile in flight as Ken Rands KR1 RG.

The standard RV4 gear standing still, looks like it's approaching Vr and it's as sexy as gears get. I'd love to get some ACM stick time against this RG -4 with my standard Lyc 0-320 FP.

Now if you want to drool and admire engineering and a fast plane with retracts, check out the "Polen Special".

Cheers, Hans

gmcjetpilot · #35 11-01-2019, 05:38 AM

Quote:

Originally Posted by skylor

For starters, it has a counter-balanced rudder which is not stock on -4's. In addition, his fuselage is a fastback which increases stiffness of the tail moment appreciably. I'm sure there are probably other mods that I'm not aware of but these are the two that stood out when I looked at his plane a few years ago.

Skylor

For starters? I have a long list of modifications, and you mention two, one of which I mentioned.

Not an expert but I got the big stuff.

Yes RV-4's don't have counter balanced rudders, but starting with RV-6's Van's started offering counter balanced rudders. Vertical/rudder with balance weight have been retrofitted to many RV-4's, not just Dave's. But good to know, I did not notice it.

I mentioned the turtle deck. Where did I say it did not add strength? I worked as aircraft (stress) structures engineer. Yes it may add strength, but it's a glorified fairing, considering Van's aft fuselage is not weak. It's done for looks and maybe a tad less drag (at the expense of wetted area parasitic drag and weight). Look at Lancair, glider's, most fast planes have very skinny aft fuselages that taper fast aft of the cockpit. Look at P-51D no turtle deck. I've never seen a RV-4 turtle deck modification, but that does not make the wings, vertical or horizontal stab stronger. Over all Dave's RV-4 is "Stock". It's not radically modified as far as I know. I believe the wing is standard span (except for custom wing tips).

You are right there is stuff we don't know about. However Dave is a very generous guy sharing his knowledge, will tell what he has done, especially during cocktail hour before an Oshkosh dinner.

gmcjetpilot · #36 11-01-2019, 05:43 AM

Quote:

Originally Posted by Saber25

Now if you want to drool and admire engineering and a fast plane with retracts, check out the "Polen Special". Cheers, Hans

That was a one off built by a corporate pilot I recall. It was sold and never heard of it again. Do you know where it is? I would love to see it in person. Remember seeing it magazines way back when.

D Weisgerber · #37 11-01-2019, 07:49 AM

Quote:

Originally Posted by gmcjetpilot

That was a one off built by a corporate pilot I recall. It was sold and never heard of it again. Do you know where it is? I would love to see it in person. Remember seeing it magazines way back when.

I raced in the Airventure Cup Race 1999 to 2004, most years the Polen Special was in the race, it is now owned by Dick Kyte, and his wife Deb (I hope I spelled his name right) They are both great people, and it is a very fast airplane. I believe he is based in Texas.

F1Boss · #38 11-01-2019, 08:56 AM

I guess I'd better keep my project to myself...RG system...supercharged engine...electronic fuel and ignition...turtledeck w/interior mods...tougher empennage...maybe even a fabric rudder...

Oops..

rv6ejguy · #39 11-01-2019, 09:38 AM

Quote:

Originally Posted by gmcjetpilot

Over all Dave's RV-4 is "Stock". It's not radically modified as far as I know. I believe the wing is standard span (except for custom wing tips).

Um, no. Many things not stock.

rvbuilder2002 · #40 11-01-2019, 09:42 AM

Quote:

Originally Posted by gmcjetpilot

Yes RV-4's don't have counter balanced rudders, but starting with RV-6's Van's started offering counter balanced rudders.

Not true.

The RV-6 was introduced in 1986 with a vertical stab and rudder that looked very similar to an RV-4 (and had no counterbalanced rudder).

The counterbalanced rudder wasn't introduced to the RV-6 until somewhere around 1998.
It wasn't done because of a perceived need. It was done for parts commonality (for the benefit of reduced parts inventory), and to update the RV-6 kit to benefit from some of the pre-punch advancements that had been made in newer kits.