Hks 700t

[Geowitz]

Yup, 2 cylinder turbo, 80HP, BUT just to clarify(and brag a little)it's a true(takeoff to 3 min max) 80HP from Sea level up to 16,500 feet(Max continuous is 79HP). Because of the turbo it out performs the Rotax 912UL from the ground up and actually surpasses the 912 ULS in HP from 7000 feet and up. Granted, the Turbo version is somewhat new, but their track record as a company overall is excellent and the reviews on the engine have been consistently great. Don't get me wrong. I like the Rotax 912's and wouldn't mind having one, but HKS is also a great, reliable, and proven company.

The 60 HP version is the same size externally, but the new turbo version is actually a longer stroke with different oiling and other internal changes. The engine has two separate ECMs each with their own injectors, ignitions, and sensors. I've got a 72 inch IVO Medium Prop with in flight adjust for it which is pretty necessary to take advantage of the consistent power at all altitudes/air densities. Total weight should be around 155 lbs with everything including prop. The power and weight fit the Kitfox IV perfectly.

I've got the smooth cowling so I'm gonna try to fit the intercooler inside, but it would easily mount where most currently mount their radiator. Since it has the same external dimensions as the 60HP it will fit in the round cowl without too much modification besides trimming in a few small spots for clearance.

[Geowitz]

Progress on the mount. I tacked it up with a mig and ER70S-6 wire. Will do the final welding with gas and same rod.

[Geowitz]

My jig worked and the mount actually lines everything up perfectly . Now, just need to figure out where everything can fit. Biggest hurdle is the inter cooler.

[rawheels]

Geo,

How did you figure out the material sizes and layout of your mount? I am supposed to go pick up a 700e on Sunday for my Model IV. I've been looking at Jerry's design down at Green Sky, but I don't like how the prop doesn't extend near the center of the cowl. Trying to figure out the design and loads for a new mount design seems very hard.

Are you using a Kitfox produced smooth cowl? If the cowl opening lines up with your prop, then the prop would be close to the center of the round cowl as well. Hmm...Do you think there is any room to fit a muffler behind the engine on your design?

Ryan

[Geowitz]

Geo,

How did you figure out the material sizes and layout of your mount?

I had a friend who is an aeronautical engineer do some load calculations for the engine weight and max G forces that could be experienced which is about 6 positive g's. With plenty of safety margin I used 5/8 inch .049 for the two bottom tubes, and 1/2 inch .049 everywhere else. The actual layout of the tubes was really determined by the five points on the firewall and the engine mounting plate. I had no choice but to to go from point A to point B while working around the exhaust pipes and while triangulating everything. You just go where you can. If you're worried you can gusset everything too. There are a few short tubes I added after these pics that really tie everything together and add more triangulation.

I am supposed to go pick up a 700e on Sunday for my Model IV.

Congrats! It's a great engine.

I've been looking at Jerry's design down at Green Sky, but I don't like how the prop doesn't extend near the center of the cowl. Trying to figure out the design and loads for a new mount design seems very hard.

Really, if you follow the typical examples out there you're not gonna have a problem. They're all over designed anyways. However, it's nice when all the work has already been done and proven. It's hard to fit the engine and muffler in any of the cowlings because of the height of the two added together. You definitely want the muffler below. The problem is not that the engine or muffler is any bigger than a Rotax. It's that the HKS uses a bed mount which takes up space below the engine. This then pushes the prop up a bit with the gearbox in the up position. You can also put the gearbox in the down position like MNFlyer - http://www.teamkitfox.com/Forums/album.php?albumid=18 . He has pics in his profile that give a good overall design. All designs are gonna require some work to modify and fit though.

Are you using a Kitfox produced smooth cowl? If the cowl opening lines up with your prop, then the prop would be close to the center of the round cowl as well.

Yes. It's the official Kitfox smooth cowl. The thrust line is basically the same for both cowls.

Hmm...Do you think there is any room to fit a muffler behind the engine on your design?

Ryan

Sorry, but probably not. The nice thing about the Turbo is there is no need for a muffler so I could arrange the tubes on the bottom a lot easier.

[Geowitz]

I like your motor mount a lot more than I do mine. Want to make another?


BTW, where are you going to mount the oil cooler and oil tank? Will you use the HKS tank or make one of your own to fit?

Fitting the muffler would be your biggest problem. I suppose if you got rid of the big canister muffler and went to a smaller muffler you could pipe it parallel to one side of the two lower supports down to the lower center allowing you to use this design. Probably stick out of the bottom a little near the back. If you put the muffler parallel to the firewall it would have to stick out of the bottom of the cowl a little too.

The oil tank will be stock HKS and go on the right side of the engine just below the tubes. With the engine lowered to the correct thrust line though this forces the oil tank lower which could get in the way of the muffler depending on how it is arranged.

Oil cooler will have to go below the engine and some slight cowling modification will be required. Inter cooler fits and will hopefully work in the back on top with ducting. Otherwise it would easily go where the Rotax radiator usually goes.

[rawheels]

Geowitz,

Any new updates on your project?