Horsepower for Weight.

[Oryx]

I’ve been interested in the recent thread on “The speed penalty for extended gear.”

To keep from drifting that thread I decided to post my question on a new thread.

If you don’t want fuel injection, how much power can you generate from a O360 without going experimental?

I’ve heard of folks:
*porting and polishing with a guaranteed 10% increase.
*cutting out the flame tubes or power flow exhaust for 5% more.
*after market air filter (=higher manifold pressure).
*higher compression pistons.
*straight boring the cylinders or over boring.

Had anyone done some or all these modifications and measured the results?
It seems very doable to have a 200+ HP Husky without the weight of an injected one.

 

[johnaz]

I’ve been interested in the recent thread on “The speed penalty for extended gear.”

To keep from drifting that thread I decided to post my question on a new thread.

If you don’t want fuel injection, how much power can you generate from a O360 without going experimental?

I’ve heard of folks:
*porting and polishing with a guaranteed 10% increase.
*cutting out the flame tubes or power flow exhaust for 5% more.
*after market air filter (=higher manifold pressure).
*higher compression pistons.
*straight boring the cylinders or over boring.

Had anyone done some or all these modifications and measured the results?
It seems very doable to have a 200+ HP Husky without the weight of an injected one.

We have done these on a Husky. If you believe Lycon dyno numbers, we have 217HP.
I am a bit skeptical on the results. Had two different motors done and dyno from another shop also showed about same HP. I find it hard to believe more HP, but 200 to me is realistic.
John

 

[Oryx]

We have done these on a Husky. If you believe Lycon dyno numbers, we have 217HP.
I am a bit skeptical on the results. Had two different motors done and dyno from another shop also showed about same HP. I find it hard to believe more HP, but 200 to me is realistic.
John

John,
That would be awesome to have 20% more power than the stock Husky.
What were the performance differences in flying the plane before and after.

 

[johnaz]

John,
That would be awesome to have 20% more power than the stock Husky.
What were the performance differences in flying the plane before and after.

One had been damaged when I did not own it and other one was a project, so did not fly either prior to the mods.
One can sure tell the difference if flying a stock one. Doubt any stock one with 35's and bellypod , half tanks, solo can take off in 80' at sea level.

 

[Flying Dave]

I’ve never been for want with the Husky’s departure but I wish I could get it to slow down a skosh more. This pilot does need to practice more though. If it had Cessna flaps…

 

[johnaz]

I’ve never been for want with the Husky’s departure but I wish I could get it to slow down a skosh more. This pilot does need to practice more though. If it had Cessna flaps…

Practice nose up, 3 point attitude. Fly down a long runway, stay 5' off the ground until you learn that attitude, use small power adjustments to fly it, ready to land but don't. You should get the feel of slow flight. If you reduce power slightly you land 3 point. Try not to land but maintain the speed ready to land.

 

[David]

I’ve been interested in the recent thread on “The speed penalty for extended gear.”

To keep from drifting that thread I decided to post my question on a new thread.

If you don’t want fuel injection, how much power can you generate from a O360 without going experimental?

I’ve heard of folks:
*porting and polishing with a guaranteed 10% increase.
*cutting out the flame tubes or power flow exhaust for 5% more.
*after market air filter (=higher manifold pressure).
*higher compression pistons.
*straight boring the cylinders or over boring.

Had anyone done some or all these modifications and measured the results?
It seems very doable to have a 200+ HP Husky without the weight of an injected one.

I have had Lycon do several engines for me. I had them port and polished and then had them dyno tested. If my memory serves me correctly, I got about a 7% increase in actual HP over the stock airplane numbers. Then, the engines were just newly built too so maybe compared to a factory new engine you might only get 4-5%. I had Lycon do all of my rebuilds/builds. I really like their work and the engines go to TBO. The down side is if you just want a set of cylinders ported and polished you are currently looking at 6-7 months. If you want them to build an engine, no matter what they tell you, expect 9+ months. Happened every time. Everyone I know says 6 months was the quickest they got theirs done in. Lycon told me that they could easily build a 200+ hp O-360 as they go WAY BEYOND this with their race engines. They said they could do this and still keep it certified. However, after a point, your actual TBO starts going way down. 195 Hp out of our O-360 would be easy by them. Call and talk to them. Great folks.

My Husky's flame cones went bad and started rattling around inside the muffler. AI would not sign it off as airworthy as the pieces could potentially block the exit of the muffler. Rather than have it rebuilt or purchase a new one, I totally removed the flame cones and had a certified welder put it back together. The AI then signed it off and I have been flying it that way for several years. Immediately after that annual, I tested it for power difference by the difference in TO distance on my farm's strip (where I had surveyed distance markers every 25 ft---used it as a long distance shooting range too). Using the same calm wind, same temp, etc. I was getting about 10 ft shorter TO. Never did figure how to calculate that into HP. It did make a difference though.

Our A-1 stock and aftermarket certified Brackett air filter is the exact same one used for the Cessna 150. I am sure if you changed the air filter size or to a less restrictive one, you would gain HP.
David

 

[Snowbirdxx]

John,

I tried to fly without any airfilter in the winter from Glaciers, where the chance of ingesting anything else but snow is extremly small. I could not see a difference in power or MP compared to the Donaldson equipped plane.
In my opinion thge carbheat box and the way inflowing air flows is the culprit. From a flow standpoint it could not be done worse. The flow entering the carb is totally disturbed and turbulent. And doing polishing and other work in these flow conditions is in my opinion wasted effort.

Larger filter and a smooth intakeducting is a must. We have some flow experts here on the forum, maybe they kick in.
<i need to look at the intake systen of a Scout / Explorer, if I see one, they are rare here. mybe parts from there can be used.

 

[Snowbirdxx]

A friend is selling his Turbine M7-420 . It is based in Italy and on N-reg N420WP. Just for those who are looking for more speed etc. 2002 452 hrs total airframe and Turbbine

 

[johnaz]

A friend is selling his Turbine M7-420 . It is based in Italy and on N-reg N420WP. Just for those who are looking for more speed etc. 2002 452 hrs total airframe and Turbbine

Thomas, did he give you the asking price?
John

 

[David]

Thomas, did he give you the asking price?
John

Here is some more info on it, but no price. https://www.aircraft.com/aircraft/200848975/n420wp-2002-maule-m7-420ac
David

 

[Oryx]

John,

I tried to fly without any airfilter in the winter from Glaciers, where the chance of ingesting anything else but snow is extremly small. I could not see a difference in power or MP compared to the Donaldson equipped plane.
In my opinion thge carbheat box and the way inflowing air flows is the culprit. From a flow standpoint it could not be done worse. The flow entering the carb is totally disturbed and turbulent. And doing polishing and other work in these flow conditions is in my opinion wasted effort.

Larger filter and a smooth intakeducting is a must. We have some flow experts here on the forum, maybe they kick in.
<i need to look at the intake systen of a Scout / Explorer, if I see one, they are rare here. mybe parts from there can be used.

I don’t know how high you were o. The glaciers but I would guess that small air filter is restrictive at a lower/negative DA.

I agree completely that airbox carb intake looks terrible. My lawn mower looks better. It would be awesome to have a bolt on solution for more flow.

 

[Snowbirdxx]

between 12500n and 14600 ft indicated alt. Box will be next project after the horizontal stab.

 

[David]

between 12500n and 14600 ft indicated alt. Box will be next project after the horizontal stab.

Thomas,

Will you be doing an STC on the horizontal stab, if it works as planned, or would we have to do a field approval? Same question on the new airbox design?
David

 

[jliltd]

The type-certificated American Champion Scout, Denali version, uses a 210hp Lycoming IO-390-A1B6. So there have been approved installations for other certified airframes.

 

[Clifford]

Totally agree with the thought that the air intake box could not be worse. I have a couple of options modeled in CAD and a welding fixture made from the stock airbox (while it was apart re-doing the carb). But I got sidetracked and haven't made anything yet. I'm still pursuing fuel injection; whether it's on the current 360; a modified 360; or a 390.

 

[dogday]

In 2017 I made a crude CFD model of Husky's air box (see attached sketch) to see if there was a simple fix such as installing turning vanes to resolve the uneven flow distribution to my carburetor. I could only find a slight improvement in flow distribution with the installation of turning vanes due to the space constraints within the air box. The problematic flow can be resolved, but it will take more than turning vanes in the existing box.

I will be ending my day job in a few months and with my new semiretired lifestyle beginning, I will have more time to pursue my curiosities.

 

[Oryx]

It sounds like there is enough interest and some real experience to have a co-operative project and a real solution.

My A1 has a smaller metal flange riveted to the lower cowling that shrouds the air filter. The stock filter (Cessna 150 size) fits snug.

I looked at an A1A and it appears that the shroud is significantly larger and the next size up filter would fit into that space.

 

[Clifford]

Oryx; I don't think inlet area is the issue. I've not done any numbers for the Husky but I have for other aircraft and the requisite inlet area is surprisingly smaller than you may think.
I'm eager to see if Dogday gets some CFD data and what it will show. From my experience the issue lies in little to no volume of undisturbed air in the plenum the carb draws from. In my designs I maximized this volume and did away with the carb heat flapper that effectively forms a ramp into the carb throat. I instead worked a carb heat inlet at the rear of the newly formed and increased plenum. It would be a fun thing to build.
But I'm still figuring out how to get a fuel injected 390 in my Husky.

 

[jliltd]

Don't forget about the certified Continental Prime IO-370 Lycoming clone. 195hp out of the box.

Prime Certified IO-370 Engines

STC'd drop in replacement for Cessna 172s and 170s. Factory installed by Piper in their new Cherokee Pilot 100 series trainer. We installed a Titan XO-370 on an experimental Javron Super Cub. The Titan moniker and X model name prefix indicates that the engine was from the Titan experimental line which basically has more options with less paperwork than the certified Prime line. We ordered it carbureted with counterbalanced crank, magnesium sump and two conventional CMI/Bendix magnetos. Bendix mags were a plus as those of us who open mags up for maintenance know that Bendix are better in the long run than the Slicks delivered on Lycomings. And for those concerned, replacing one mag with a SureFly SIM or an Electro Air electronic ignition basically eliminates hot start issues associated with fuel injected engines and neophyte pilots. Back on track, the 370 was a smooth powerful engine and impressed pilots all the while sounding great to ground observers. It climbed like a scalded ape. The tapered-fin cylinders have more surface area than a conventional Lycoming O-360 and the fins are bigger where the cylinder heads are hottest and taper to smaller fins to where the cylinder barrels are cooler and have a more consistent temperature distribution from case to head. So the 370 runs at cooler CHTs than a Lyc O-360 all else being equal. The inter-cylinder baffles on the 370 are tapered to match the cylinder fin planform. Our Javron didn't exhibit the CHT heat issues that is the Achilles heel of conventional factory 360 installations in "Super Cub-esque" aircraft. Basically the 370 is all the fun of an angle valve with the weight and dimensions of a parallel valve. I was very impressed by the 370 Continental Lycoming clone and the Prime/Titan replacement parts like cylinders are much cheaper than 390 equivalents.

LInk to an article on the Javron:
Chasing a Javron