Lycoming engine O-320 in a 4-place Bearhawk

[whee]

I thought there was a BH flying with an O320? I swear I read about one back in 2013 or so.

My first Bearhawk experience was an hour flight with a friend in his 260hp BH and man was it fun. Loads of power. Then I put about 40hrs on a O360 BH. The engine was one of Bob angle valve low compression engines. He used to list them at 170hp but when I talked to him he said they put out 180hp and that's how they list them now. I found the performance to be satisfying; good enough to do what I wanted to do. When I compared numbers with my O540 BH friend I realized he had gobs of STOL performance but could pull the power back to the same fuel burn I was experiencing and be flying faster, but only by a few mph.

IMO, there is no reason to install an O320 unless you had one laying in the shop but even then I'd say sell it and buy a bigger engine. I think you'd be disappointed with the performance and you'd be severely limiting what you can carry because your CG would run aft quickly. But there is no doubt the O320 would work and depending on your mission could make you happy.

I installed a 210hp Continental IO360 for a variety of reasons. I haven't flown yet and already I find myself laying in bed planning a IO520 or 550 installation Maybe I should have listened to Mark Moyle...

[svyolo]

Concur with Whee;
My adult life was flying airplanes. Some could take off in a lot less distance than they could land. Some, just the opposite. My 40% completed QB kit is the first airplane I have owned.
I think the BH is a bit unique in that it can be powered by a 260# or 450# engine, and the useful load may not change. Try that in an RV7 or 8. They call them Super 7 or 8. Basically single seat airplanes that take off like a Pitts. But they carry 1 person and a toothbrush.

If you live at very high altitudes, a 915 might make a lot of sense in a LSA or Patrol. In a 4 place, I would guess probably not. I am 100% sure I would be happy with a 180 hp Bearhawk most of the time. As a matter of fact I plan on flying mine LOP at that HP or below, even in climb out. If you live in Leadville, I would probably choose a turbo O-360.

In theory, I chose a 540 powered BH for a lot of pragmatic reasons. Cheaper and simpler than a turbo, same FF when pulled back on power. I have no intention of cruising at 160 indicated.
In reality, I get an airplane that is almost as good as a turbo o-360 at altitude, can carry a lot, and when I need it, I can take off in a very short distance.

If I lived in Leadville, I might still choose the turbo o-360. If I lived in Louisiana I might choose the IO-390 I chose a 540. I would be happy with any of the three. But probably not the Rotax 915. In the BH LSA it would rock.

The IO-540 is cheaper than any of the other options.

[Chris In Milwaukee]

I only mentioned the 915 because it's the biggest thing Rotax makes at the moment. But yes, the big-bore airplane engines are hard to beat in this case. Although I've never flown behind one, I think that Jon's choice of a Conti 360 is a great one.

[Bcone1381]

Another data point....cost. When I was first contemplating engines options for the Patrol, I talked with Bob Barrows about O-320 vs O-360's. I was leaning towards light weight. Well, he can build an O-360 for about the same price as an O-320. Free horse power! I'll take the weight hit!!

About Weight. The weight of an O-360 can vary by more than 20 lbs. The Hollow Crank (fort constant speed props) saves weight over the solid crank (for fixed pitch props), and so does a Narrow Deck case. Angle Valve cylinders (used on the 200 hp IO-360-A series engines) add quite a but of weight too, meaning an O-360 weight can vary in weight by 20 pounds or more. I had Bob build a narrow deck, hollow crank, IO-360 with Parallel valve cylinders, and Bob said it weighed about 270 lbs. Searching the FAA TCDS lists weights of different variants was educational.

[svyolo]

The RV guys seem to make the same choice a lot of the time. The primary reason to choose a 0-320 is because you already have one, or get a smoking deal on one. They cost difference is minimal. There is a slight weight penalty, but you get 20 hp for little additional cost.

[geraldmorrissey]

For those of you who are considering modifying 0320's or 0360 to increase horsepower, go to the Biplane forum. The Pitts/Skybolt/Eagle etc pilots have a wealth of practical knowledge on the subject. Though their mission is different, it's still interesting reading.
Gerry
Patrol #30 wings

[Chewie]

So are we saying a 320 would hurt load carrying ability vs a 360 because of CG? Are the moment arms of each installation the same?

[marcusofcotton]

The lighter the nose is, the less you you can put in the rear baggage due to aft CG. Certainly can, even likely to, become a limiting factor, certainly has for some. Battson has written some on his experience.

Experimental Amateur Built is for educational purposes, this is definitely an area to become educated on. : o )

[Bcone1381]

Don't let the empty weight CG of your build be a mystery. Visualize how it might change based on decisions that will be made now, rather than later. Set goals for it, Control it and calculate what it will end up as you build. Buy a scale for your shop.

This will force a builder to make choices like the placement and type of Battery, prop, engine, engine mount, etc. If the algebra of "Weight x Arm = Moment" is a bit over someones head, maybe we could have a discussion on that. The choices that the CG goal could end up reducing the cost of your build, like if a bit more weight is needed up front, a metal prop instead of a composite prop might be the better choice.

Like Marcus says, a light O-320, no electrical, no Battery, with an 8 pound compost prop would have a more aft empty CG. Everything that gets loaded into the airplane moves the CG aft.

[Chewie]

Right, but specifically I'm curious if the installations between a 360 and a 320 are the same. Is a 320 installed farther out typically to account for CG?

[Bdflies]

I've never flown an airplane that I could take off shorter than I could land. From a 172 to radical singles to turboprops to jets. More power is always better. And a 180hp 360 is like 30lbs heavier than 160hp 320.

No doubt pilot skill is the biggest factor at play here. Which is to say that I need to hone my landing skills. It’s my impression that serious bush planes, like Supercubs, Huskys, Maules and Bearhawks will consistently take off in a good bit less distance than landing. Turboprops and jets have thrust reversers that significantly augment the brakes. Our 'rag and tube' taildraggers don't enjoy such. I can get my (admittedly heavy)Patrol off in about 130’, 1/2 gas and no wind. I think I'd need a tail-hook to stop it that fast. About a thousand hours in Huskys was the same. I've always considered that fact a safety factor; If I can land someplace, it will definitely get out.

I'd like to hear others' impressions about takeoff / landing distances. If I'm the only one who can take off shorter than land a Bearhawk, I definitely need to work on landings......

Bill

[whee]

Concur with Whee;
My adult life was flying airplanes. Some could take off in a lot less distance than they could land. Some, just the opposite. My 40% completed QB kit is the first airplane I have owned.
I think the BH is a bit unique in that it can be powered by a 260# or 450# engine, and the useful load may not change. Try that in an RV7 or 8. They call them Super 7 or 8. Basically single seat airplanes that take off like a Pitts. But they carry 1 person and a toothbrush.

If you live at very high altitudes, a 915 might make a lot of sense in a LSA or Patrol. In a 4 place, I would guess probably not. I am 100% sure I would be happy with a 180 hp Bearhawk most of the time. As a matter of fact I plan on flying mine LOP at that HP or below, even in climb out. If you live in Leadville, I would probably choose a turbo O-360.

In theory, I chose a 540 powered BH for a lot of pragmatic reasons. Cheaper and simpler than a turbo, same FF when pulled back on power. I have no intention of cruising at 160 indicated.
In reality, I get an airplane that is almost as good as a turbo o-360 at altitude, can carry a lot, and when I need it, I can take off in a very short distance.

If I lived in Leadville, I might still choose the turbo o-360. If I lived in Louisiana I might choose the IO-390 I chose a 540. I would be happy with any of the three. But probably not the Rotax 915. In the BH LSA it would rock.

The IO-540 is cheaper than any of the other options.

Thanks a lot svyolo. I just wasted an hour nerding over how to install a turbo on my BH.

I don't consider my 4740msl home elevation all that high but when summers DAs approach 10K a turbo may be a better option than more engine displacement. With modern electronics a turbo could be much simpler and reliable than the old school high maintenance springs, androids and vacuum lines used on certified planes.

[zkelley2]

No doubt pilot skill is the biggest factor at play here. Which is to say that I need to hone my landing skills. It’s my impression that serious bush planes, like Supercubs, Huskys, Maules and Bearhawks will consistently take off in a good bit less distance than landing. Turboprops and jets have thrust reversers that significantly augment the brakes. Our 'rag and tube' taildraggers don't enjoy such. I can get my (admittedly heavy)Patrol off in about 130’, 1/2 gas and no wind. I think I'd need a tail-hook to stop it that fast. About a thousand hours in Huskys was the same. I've always considered that fact a safety factor; If I can land someplace, it will definitely get out.

I'd like to hear others' impressions about takeoff / landing distances. If I'm the only one who can take off shorter than land a Bearhawk, I definitely need to work on landings......

Bill

No all the Bush planes land shorter than they take off. I can't think of a single airplane that this isn't the case. Provided the pilot is capable. Taking off is a lot easier than spot landing.

The reverse on turbines is not factored when considering landing distance. So that isnt a factor.

[Mark Moyle]

Lycon built an O-320 using their ported cylinders, 8.5-1 pistons. Non integral cam shaft with 2 degrees of advance...only manufactured for 2 years...I’m told. Leading edge exhaust and -32 carb. Produced 197 hp on their Dyno. I’ve built the same for my Pacer.

On my IO520... weighs 462 pounds with everything but the baffles above the cylinders. Is equipped with the large 1200 series bendix mags, full size starter motor and alternator. Have light weight starter and alternator now... may change to electronic ignition...will be selling my 3 blade McCauley prop and use an MT...should be able to get the total firewall forward weight down to that of a O-540 with a constant speed metal prop. 14 or 17 pound carbon fiber cowl will help. Don’t recall the exact weight of the cowl....

I’m also going with an MT prop on the O-320 using the STC for the PA 18. I did have a Borer prop 82/42 on the engine...needed a legal prop for Marv’s Pacer...I rebuilt his O-320. 160 hp with the Lycon ported cylinders.. it’ll get off the ground shorter than landing with just me and 18 gallons of fuel..shortest landing so far is about 250 feet. Marv’s Pacer needs an 82/44 to keep the RPM Under red line at max at Vx. The PA22/20 weighs a tad over 1250 with 29” bushwheels and a set of 199-62A Cleveland wheels and brakes...Scott 3200 and allot of paint...horrible paint job...it’s a 30’ paint job. The down side to getting off short is a lack of speed at the top end...right at 97 mph at 2450 RPM.

[whee]

No all the Bush planes land shorter than they take off. I can't think of a single airplane that this isn't the case. Provided the pilot is capable. Taking off is a lot easier than spot landing.

The reverse on turbines is not factored when considering landing distance. So that isnt a factor.

Maybe I'm reading your post wrong but your statement seems to be incorrect. Just take a look at the Valdez results where pretty much every takeoff is shorter than the landing.

http://www.valdezflyin.com/wp-content/uploads/2017/05/2017-Valdez-STOL-Final-Results.pdf

[zkelley2]

Maybe I'm reading your post wrong but your statement seems to be incorrect. Just take a look at the Valdez results where pretty much every takeoff is shorter than the landing.
http://www.valdezflyin.com/wp-conten...al-Results.pdf

Valdez is.... not real. No one flies like that. Doors off interior torn out and 35 minutes of fuel.
Put a realistic load in it and throw takeoff roll goes up significantly while the landing roll doesn't so much.

[zkelley2]

Looks like the Mackey Cubs can do it.


A real stol competition.