Info needed for Rotec radial install in Model 4

[cubtractor]

Glad you got down safe Lynn. The radial will be awesome.

[avidflyer]

I have no experience with the radial engine. Was just emailing back and forth a week or so ago about someone who wanted to put a radial on their Kitfox. That prompted me to go look at some videos on utube of the radial in Kitfoxes. Just out of curiosity I counted how many seconds it took to get off the ground in these videos, and some were around 12 seconds. That did not seem impressive to me at all. I don't know the what the weight or density altitude was and that would make lots of difference, but I was surprised it didn't do better. One video is the Kitfox factory plane when it had the radial on the nose. Wonder what the John Mcbean's comments would be. Great sound no doubt, I wonder about the performance. Aren't they supposed to be making 130 HP? Not trying to sound critical, I was just surprised by what I saw. If you're flying floats, all the more reason to be concerned about takeoff performance. Jim Chuk
https://www.youtube.com/watch?v=97dO-pq03Qs
https://www.youtube.com/watch?v=TL1kVB7e7FE

PS did a bit more checking and see there is a 110 HP model radial engine. That is probably what is being used on these planes. I looked here:
http://www.rotecradialengines.com/0RotecR2800/R2800.htm
it says the engine is 224 lbs dry (almost 100 more than the Jabiru) fuel burn is 5.82 gph, although it doesn't say what the rpm is for that fuel burn. Again I'll say this, I'm not trying to bash this engine, just mentioning what I found out. YMMV

[DesertFox4]

Lynn, Kitfox Aircraft has the firewall forward kit that might save you time and money even if it is for the model 7. You will need longer gear to have enough clearance to swing a big enough prop to put that 130 hp to use. Battery goes in the tail and I beleive the wings were swung forward for C. of G. considerations on Bill's model 4 in the photo I posted.
Go back and look at the Kitfox of the Month for June 2010 " Little Red". Bill may have been the first to go through this process.
image.jpg

As to performance, I was the one taking the video in the 2nd youtube video that Jim posted. You do not firewall this engine like you might a Rotax. It has a fair amount more torque and on those longer gear P factor is prevalent. I counted 8 to 9 secounds and Bill was very easy on throttle application. I know that engine will set you back in the seat even with a smooth steady roll in of power more than my 100 hp. Rotax could acheive. Climb out was evey bit as good as my 912 uls or better with two guys and full fuel. I think Rotec is right on with their 130 hp claim.

Be aware Lynn that this engine is no jump in the Kitfox and hit the starter go fly kind of engine. It is a real radial requiring all the fussing that those engines demand. Draining oil from the bottom cylinders is an unavoidable routine start up necessity. It marks it's territory everywhere it sits for any period of time.
Best of luck with the project.

[Danzer1]

Okay, I'm going to chime in here. Like Jim and many others, I have been on a quest for finding alternate engine choices.

I will preface this by stating:I am a proponent of documentation of claimed performance (dyno charts) and abhor anecdotal and hearsay claims. I also could care less about HP numbers, but do care where peak torque occurs and what the rest of the torque curve looks like. I also care about fuel consumption and total weight.

I to was enamored with the sexy round radial look and in 2013 investigated the R2800 as far as I could. Jim is spot on with weight - it is a heavy engine!

In my quest, I contacted the factory and asked for a copy of the dyno test results so I could see for myself the HP/Torque curve and associated fuel burn.

In response, I got a lengthy email from the owner, pretty much touting all the testimonials by users, that can all be found on their website. Which by the way hasn't been updated since 2014. I did however glean a few "facts" from him. I say "facts" in quotes as he refused to share any dyno charts. He did state though, they dyno'd it once in 1999.

He stated: it produces "110 HP at 3600 rpm" which equates to 160 Lb.ft. of torque at the engine with a 3/2 reduction or 240 Lb.ft. at the prop. Pretty good!

However, he stated, "it consumes 32 liters/hr" doing it (WOT) with the Rotec TBI (optional). That's a hair under 8.5 gph - not so hot!

The only other "fact" I could glean was that he says it consumes "around 20 liters/hr at cruise" (again with the Rotec TBI). He did not state the power level or rpm that occurred at, but that still equates to 5.28 gph - also not so hot.

Besides that info, what turned me off was:

If the engine performs as claimed, why not share the dyno results?

His 2nd to last paragraph asked if I was ready to put down a 20% deposit and asked for me to do so at the upcoming Copperstate Fly-in. Kind of presumptuous seeings he wouldn't provide any hard documentation!

And lastly, his last paragraph killed it for me. He referred to the additional 6 pdf testimonials he attached to the email and stated (and I quote): "if there is still not enough evidence here to convince you to buy our R2800 engine, then I hate to say it, but you ain’t ever buying a Rotec!"

Well guess what? I guess I "ain't"!

Cheers, Greg FWIW

[DesertFox4]

In my previous post I typed 130 hp when it should be 110 for the 2800.
Apologies for not catching that.

[Lynn Matteson]

[QUOTE=DesertFox4;58221]Great save Lynn.


Thanks.....I used to hear that all the time when playing goalie on an ice hockey team....now I hear it too often while flying....


Best of luck on the Rotec install.
Here is some visual insperation.

[jmodguy]

Lynn
Go for it! There will always be naysayers and some that say this or that. It is known that the Kitfox will fly with the radial. That should be enough. If you like the sound of a radial then go for it! I was considering a Rotec until I decided on an IO-340. Got some negative feedback here and then Kitfox posted some pretty neat info on their website... An O-340 on a Kitfox SS.
Hmmmm
DO IT! I triple dog dare you!!
Jeff

[HighWing]

Lynn,
I do remember the olden days. I think you have proven that you can make things work. I'd just say - Go for it.
Lowell

[Dave S]

Lynn........ Highwing's comment "I do remember the olden days." came back to rest on my shoulders today as my wife and I got back to the home 'port with our Kitfox to find some radial powered warbirds (AT-6's) practicing up for their July 4th formation and overflights & smoke they do in conjunction with our liberty celebrations. Had to stick around and watch & listen...particularily thinking about how these engines powered the many craft which had a lot to do with why we celebrate our days of patriotism such as this weekend.

There really is nothing like the sound & fire of these engines starting up and taking off. I'll agree....it's a lot of nostalgia mixed with testosterone poisoning that really thrills a person at the sound of a radial. I don't have one but am grateful for those who do.

You know.....as a group, we are really about trying things and experimenting with what strikes our fancy; and thank heavens we don't all do the same thing That's what keeps it interesting.

There is grace, gratitude and satisfaction in persuing our dreams and I seriously doubt that any of us would rest on our deathbed when we are 110 years and say: "gee I wish I hadn't built the plane I always wanted" - not gonna happen.

Persue you dreams....

[Lynn Matteson]

Lynn
Go for it! There will always be naysayers and some that say this or that. It is known that the Kitfox will fly with the radial. That should be enough. If you like the sound of a radial then go for it! I was considering a Rotec until I decided on an IO-340. Got some negative feedback here and then Kitfox posted some pretty neat info on their website... An O-340 on a Kitfox SS.
Hmmmm
DO IT! I triple dog dare you!!
Jeff

I've got plenty of naysayers around here, but that just spurs me onward.
I'll take that triple dog dare...now where's that frozen flagpole? : )

Lynn