Show us a pic of your RV-4 !!!

[DeltaRomeo]

(Instructions on inserting images into messages can be found at http://www.vansairforce.net/articles...ums/images.htm)

Let us see some pics of your finished RV-4.

Best,

[DeltaRomeo]

Taken Dec 17th, 2004 (100yr anniv. of powered flight)

[Andy Duff]

Thought I would see if I could insert a picture. If it works, this is my RV-4. I enjoyed the building phase so much, I stretched the construction time over 15 years, ha. First flight was April 2004. Currently have 165 hours on it. Powered by O-360-A1A with Whirlwind 151 prop. Currently trying a set of sheared tips on it. Picture was by Gary Robertson in Borrowed Horse (with Jay)

[garnt.piper]

Hi, great idea about the piccies.

I 'loved' the building process so much I too made it last 14 odd years (an almost scratchbuild). First flight 20 June 2003, just finished the paint (it's v.dark green, not black). New O-360-A1A with Hendrickson wood prop, Ellison TBI, Raven inverted oil systm, 4-1 exhaust, no lights, no gyros, ~950 lb empty. Currently flying Sportsman aerobatic comps in it OK but wish it rolled faster!

Question - I thought the Whirlwind -151 prop was restricted to counterweighted -360's only?? Confirm.
Grant Piper
Australia

[CBRXXDRV]

Purchased N42917 already built and flying one year ago.
0-320 w/CS prop. Based @ LAL. Also Building an RV-8

Sal Capra

[Andy Duff]

Grant,
The Whirlwind 151 is permitted on a non-counter weighted crank O-360. However, there are RPM restrictions, and Whirlwind does not recommend the 151 with high compression pistons or electronic ignition. The RPM restrictions are as follows: avoid continuous operation between 2050 to 2300 and 2600 to 2700 RPM. If you want more information there is a Whirlwind support group on Yahoo. When I joined, I asked a question right alone the line of what you are asking, that is what is the effect of a light weight prop (the 151 is 28 lbs) on the non counterweighted O-360. There was previous talk/rumor of fatigue issues on the engine accessory drive due to rotating system resonance potentials. The link to that site, and my first post is as follows
http://groups.yahoo.com/group/whirlw...ers/message/23
Hope this helps.
Andy

[bullet]

Andy, on your sheared tips, who's were they? Results?

Thanks
Gary

[garnt.piper]

Thanks for the gen Andy, will read back on the topic. Mine is standard A1A 8.5:1 comp. What is your opinion on the prop? Do the restrictions bother you much? I find with my fine prop at cruise I run at 2600+ quite often, though with a C/S I could pull that way back. Have you done many aeros with it? Does it govern quickly and hold the revs out of the restricted ranges? I like the low weight, I'd need to change to the short cowl and 13" spinner to suit.

Grant

[Andy Duff]

Gary,
The sheared tips are Vans. As far as performance, it is too close for me to call. Vans tips have more of a rounded edge which are rumored to have better speed performance than the competitor...but it's all pretty close. I would like to think I got a knot or two, but it was more about the look for me. Personal preference, but I like the way the sheared tips break up the Hershey bar look in plan form. I also like being able to get the tip lights inside a fairing. (There are others at my field that would disagree, but that's what makes for friendly banter. I may switch back to the Hoerner style if one of the guys at the field starts to tell me he likes the sheared tips!). The tips add wing area, so stall speed should be a bit lower, and roll rate a bit slower, but again, to close for me to tell.

Grant,
My Sensenich had an 86 pitch. I was lucky if I got somewhere between 1900 - 2000 static, so I was missing out on quite a bit of power on takeoff and initial climb out. Even with this fairly aggressive cruise prop, the airplane would still unload and allow me to exceed 2700 rpm at full throttle. In addition, keeping up with the 180 hp constant speed crowd flying out of Hicks required over 2600 rpm when they were at 24 square. (Pushing too hard for my liking)
The choice for the 151 was pretty simple for me. I had a long cowl (with 12" spinner) and short gear. Since I didn't want to switch the cowl, I needed a CS prop with extended hub. Hartzells with extended hub for the O-360 were too heavy for my liking, and just about as expensive as the Whirlwind. The 3-blade prop is 68" in diameter and that helps with the short gear. Additionally, the Whirlwind 200RV is not available in an extended hub version so that was out of the running. I used the Lancair spinner (sold for the 151 by Whirlwind) since it is just a shade over 12 inches in diameter. (I did end up refairing and repainting the cowling to blend the spinner a bit better....I could have lived with the minor mismatch, but I'm anal-retentive like that)
In the end, I got 14 lbs off the nose by switching to a constant speed prop. The aircraft still unloads well. I typically run 20 inches at 2400 rpm when the 6s are running 24 square. With respect to aerobatics, the 151 goes flat with no oil pressure, for serious aero you want the blades to go course with no pressure. I typically only do rolls & Immelmans so I really don't get into many things that require quick transients. But I will say that the 151 has a fairly small actuation piston requiring high (475 psi) relief pressure in the governor. That coupled with the very low inertia of the prop make the prop hunt more that others with rapid throttle transients. (Again, counter to what you want for serious aerobatics)
For the way I fly, I love the prop! Everything is a compromise, but I don't find the RPM restrictions to be a problem, and the the climb, cruise and braking performance more than make up for the drawbacks. IMHO

[jhallrv4]