First Flight - HKS700T Speedster

[Geowitz]

Just a quick update. Have about 12 hours total time so far and everything has been running great, knock on wood. The engine really is great! It never skips a beat. Just have to figure out the best prop combo - Not much in the way of field experience yet so it's pretty much up to me.

Been running a 71 inch Kiev for about 5 hours. The 71 has great thrust and climb if pitched appropriately, but doesn't quite have the cruise I was hoping for. About 105mph when pitched for cruise. May be able to try out a 67 inch version on loan soon. From the sounds of it in some older posts the shorter prop may be the ticket.

Worked out some of my vibration issues by adjusting my rubber isolators so I may try the IVO again too.

Still got the grin

[Geowitz]

Update - About 23 hours as of today. Engine still never skips a beat. So far I've tried three different props. Finally had time to do 180 degree opposite GPS tracks to average for true airspeed so kindly ignore my indicated speeds from before. I still have not added strut fairings or closed up the hole around the horizontal stab so eventual speeds will be considerably higher.

Just to recap - max rpm is 5300(2000 prop rpm), max continuous is 5000(1900 prop rpm)

All flights were as close to the same weather conditions as I could get. About 60 degrees F at the ground. Airport is 85'msl.

Ivoprop, 2 blade, 72", medium, in flight adjust -
Max climb at 60mph WOT 5300 rpm - 1100fpm
Cruise with prop pitched to 5000 rpm at WOT- 105mph

Kievprop 163, 67.3", 3 blade
Pitched to 5100 static, Max climb at 60mph WOT(5300rpm) 1200fpm, Max cruise at 5000rpm - 92mph

Pitched to 4700 static, Max climb at 60mph WOT(4850rpm) 750fpm, Max cruise at 5000rpm - 99mph

Kievprop 183, 71", 3 blade
Pitched to 5100 static, Max climb at 60mph WOT(5300rpm) 1400+ fpm, Max cruise at 5000rpm - 90mph

Pitched to 4700 static, Max climb at 60mph WOT(4800rpm) 1100fpm Max cruise at 5000rpm - 97mph


Conclusions - So obviously the IVO gives the best overall performance... big surprise there. I was hoping the Kiev would be close enough to make the IFA feature of the IVO more of a novelty than a performance gain, but with a max prop speed of 2000rpm I don't have as much of an envelope for one pitch to give great performance in both climb and cruise. I am still, however, going with the Kiev 183. The IVO is very heavy and as noted in previous post the moment of inertia makes start up quite violent at times. The IVO definitely also has more noise and vibration throughout the RPM range. I'm more interested in comfort at this point and when I am able to make some speed mods(strut fairings, gas caps, etc...) if I can get it to 110mph TAS cruise I'll be happy with that.

Went to just under 10,000 feet today. What a beautiful view and the engine loved it! Climb at WOT was still 850 fpm.

[Dorsal]

Sounds like fun.

[Geowitz]

Yeah, snuck away early from work today. What a great way to play hookie!

[t j]

That's very informative information Geowitz. Myself, for my Kitfox mission, I consider the performance you got from the 71" Kiev to be the best performance of the three.

I suspect you will gain 8 to 10 mph in cruise speed with wing strut fairing.

[napierm]

After the strut fairings, consider the gear. Because of the slipstream the area behind the prop is in the highest airspeed but is often the dirtiest part of the plane. A rectangular gear leg has a coef. of drag something like 0.5. A simple wrap around fairing can drop that to something like 0.01.
http://www.bd5.com/bededesign.htm

http://www.bd5.com/BedeDesign18.jpg

http://www.bd5.com/BedeDesign06.jpg

Another source of drag with the grove gear is the 1" gap between the center of the gear and the fuse if you have a flat bottom w/o a radiator just in front. I've been thinking about a fairing just in front and behind the gear just level with it unloaded (gear off the ground).

[airlina]

Some Photos from my builders log on how I faired my Grove gear to the fuselage. First photo shows foam molds ready to be fiberglassed. Second photo during fiberglassing. And third shows fairing in place on bottom of fuselage awaiting Grove gear. Bruce Lina N199CL

[Geowitz]

Airlina,

Very nice. I imagine I could just form that up, leave the foam in place and bond it straight to the fabric.

[airlina]

Thanks Geowitz, If you look closely at the last photo you can see that I left a flange of fiberglass that has attachment holes drilled in it. As the anchor to the fuselage, I used scotch welded plain clamps (like adels but minus the rubber) around the tubing and rivnuts thru the plain clamp holes. This provided the threads for the AN 526 screws to hold the fairing in place without drilling thru any fuse tubing-works good lasts a long time. Bruce

[napierm]

Cool! I've never heard of an easier way to add a tab where needed.

Thanks,

Mark
(Slapping forehead with hand.)