Will a 914 Fit in a Model III?

[pedro10012000]

I've been reading about the HKS 700 Turbo - maybe it'd suit you - 80hp turbocharged, lighter and supposedly more fuel efficient than a 912.

http://www.apsu-hks.com/HKS_APSU_-_HKS_700T.html

http://www.greenskyadventures.com/En...-912Rotax.html

[predmond]

Thanks for the info on this engine. Very interesting. Does anyone know how many installations they have and how they're doing? I'd be a little concerned about only two cylinders.

[Geowitz]

Thanks for the info on this engine. Very interesting. Does anyone know how many installations they have and how they're doing? I'd be a little concerned about only two cylinders.

Hey guys. I'm actually going to Greensky Adventures in a few weeks to see the actual 700T and we are going to brainstorm about putting this engine in my model IV. When I get back I will post my thoughts and maybe some pics. I'm pretty optomistic and I think if you make yourself familiar with HKS's history your concerns may be minimized on the two cylinder thing. If I do choose to use it I will be ordering one in November.

[Geowitz]

For anyone who's interested - As I mentioned below in this thread, I just went to see the new HKS 700T and am feeling good about using it. I think it deserves it own thread so I'm going to start a new one. I've got a few photos that I will post tonight along with some other relevant info so you can follow along as I figure the install out.

[kenjfrance]

I have a 914 w/Hoffman CS prop in a Mod. 4 - 1200 and bought the firewall forward from Rotech Research in Vernon, B.C. They had a Speedster built to use as a test bed for this engine and the mods were as follows: new engine mount about 4" forward of 912 (for airbox). Split cable throttle (McFarlane), 4" aluminum extension of front cowling section, oil tank side mount with bump in rear cowl to accomodate, dual MaP and Fuel Pressure guage, NACA scoop on lower front cowl (starboard) for intake to turbo, lowered radiator. Mount is likely biggest obstacle. C-FYSM now has 940hrs. Performance @ 10,000' is 1,200fpm solo and probably 200 less @ gross.
Full Lotus off the water in 6 secs. Pulls to VNE (125mph) Cruise is 108 mph. Can't say enough good about this airplane!

[av8rps]

I didn't really have to decide as when I purchased my plane it already had the IVO 3 blade IFA. It was originally a 72", but on the first flight off the water I destroyed about 4" of the prop tips from water erosion (I installed plastic prop tape thinking I wouldn't have to use the metal tape that IVO supplies - dumb move). So I ended up cutting that prop down to 68", which lucky for me turns out to work quite well on the 80 hp 912ul. In fact, most agree the 68" works best on the 912ul, but for water work a slightly longer prop (72") is likely to provide better takeoff and climb performance while only sacrificing a bit of top speed.

So if you buy a 72" and find the performance not to be to your liking, you can cut it down to a smaller diameter like I did. But it is just so hard to make a short blade longer

[kenjfrance]

Thanks so much for the very informative reply. Which size Full Lotus? Did you have to add aft ballast to remain within CG?

I have 1260's and have my ELT mounted in the tail, as well as the battery. Getting the battery back there with a structurally solid mount and accessibility was a test with a fully covered aircraft, but it worked out well and weight and balance now is about 11" on floats, and 13" on wheels. Originally, when on wheels, I was right on the forward limit with the smallest pilot and minimal fuel....when on floats, it would have been a full 2" forward of the limit. I tried to mount "Flying Sportsman" amphibs, but when all was said and done, I was going to need to add an additional 20# of dead weight to the tail including the battery move. I gave up on that after much effort, and now fold the wings back and have it on a flat trailer and launch it like a boat, putting it back in the hanger on the trailer at the end of the day. I have an "M" design float attachment that seems to give some extra rigidity to the floats, and I don't have the "high pressure" insert option at the step. Correct air pressure in the floats is critical.....porpoising can be an issue, but technique seems to be the issue there. ( I feel I have the hang of it now) The best part of the Full Lotus, other than weight, is the ability to run it onto any beach....rocks and sharp stuff do little damage as compared to aluminum or composites. Where I live, (Southern B.C. Interior....mountainous) I leave 1,500' and go to 9,000 or 10,000' on nearly every flight, and have to "pinch myself" to be sure I'm not dreaming, it's so much fun!

[predmond]

I have 1260's and have my ELT mounted in the tail, as well as the battery. Getting the battery back there with a structurally solid mount and accessibility was a test with a fully covered aircraft, but it worked out well and weight and balance now is about 11" on floats, and 13" on wheels. !

May I ask what your empty weight and mgw are?

Because I have amphib gear on my Full Lotus, the empty weight of the Mk III is 849, with a mgw of 1200, so I've figured out that trying to put a turbo in it just isn't going to work. Too heavy and too far forward weight.

I'm going to try the IFA IVO and hope that helps a lot. Right now, with the original fixed wooden CSC prop, it only makes around 5100 rpm on takeoff run. I've been reading the other thread about prop choice with interest. IVO recommended the 3 blade medium 68" for my 80 hp 912ul. I'm going to ask them why. It seems that a two blade 72" would be more efficient.

P

[av8rps]

Because I have amphib gear on my Full Lotus, the empty weight of the Mk III is 849, with a mgw of 1200, so I've figured out that trying to put a turbo in it just isn't going to work. Too heavy and too far forward weight.

I'm going to try the IFA IVO and hope that helps a lot. Right now, with the original fixed wooden CSC prop, it only makes around 5100 rpm on takeoff run. I've been reading the other thread about prop choice with interest. IVO recommended the 3 blade medium 68" for my 80 hp 912ul. I'm going to ask them why. It seems that a two blade 72" would be more efficient.

P[/quote]

If you are only getting 5100 on your takeoff run that is killing your off the water performance. My first prop on my 912ul Kitfox amphib wouldn't pitch flat enough, so I could only get similar rpm. Off the water performance absolutely sucked! Sure, it still worked, but probably only because I am only at 1100 msl around here, and generally cooler temps. Once I got full rpm for takeoff with the new prop I cut my takeoff time in half, or better.

That wood GSC is a pretty prop, but the IVO will make a lot more thrust. Some friends over the years switched out their GSC's and were shocked at how much better their airplanes performed after the change. So I really think you are on the right track.

I'm surprised IVO recommended the medium for the 912ul. The medium blade has a minimum pitch of 30" with a max of 90", whereas the IVO "standard UL blade" has an 18-52" pitch range. That means it is much flatter than the 30" pitch range of the medium, which willl allow the 912ul to spin up quicker, getting the max power of 5800 rpm for takeoff. I am POSITIVE the 30" minimum pitch range of the medium blade will not let your 912ul get to 5800 rpm for takeoff, much like the "Plus" or "Patriot" UL blade that has 35" of minimum pitch, which are the blades that I had before and wouldn't let my 912ul spin up beyond 5100 rpm for takeoff.

Also worth mentioning, at the other end of the pitch spectrum, my 912ul also can't handle more than 52" of pitch. So having a blade that can go to 90" (like the medium does) will be absolutely useless with a 80 hp 912ul.

I really am thinking someone at IVO must have misunderstood and thought you had the 100 hp 912?

Here's the info showing IVO's pitch ranges and blade types;

IVOPROP Electric In-Flight Adjustable Ultralight Model
For engines up to 100 hp
18"-52" pitch range (Standard UL blade) **
or 35"-70" pitch range (Plus or Patriot UL blade)
48"-72" diameter


IVOPROP Electric In-Flight Adjustable Medium Model
For engines in the area of 100 hp or high ratio gear boxes
30"- 90" pitch range
52"-74" diameter

** The prop that works very well on my 912ul amphib is the 18-52" model UL blade. With that prop I can actually get more than 5800 rpm for takeoff, so you need to be aware and make sure not to overspeed your engine (IVO washers can be used to control overspeeding issue).

[dholly]

Thanks for the info Paul, that post is very helpful to me. Another good reason to check all new posts regardless of subject line! Regards, Doug