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Post #11 in this thread under "Trip Reports" has a first hand comparison between a Bearhawk and a C-180 with a Pponk engine conversion on a trip to Alaska.
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Brooks Cone
Southeast Michigan
Patrol #303, Kit build -
I wouldn't consider trim tabs a negative; many airplanes use them and they work fine. I don't think a PF trim system is a must do item I chose to do it because I'm be flying with a really aft CG a lot and in that situation it will be beneficial. There are plenty of other BH pilots that fly their planes at aft CG and don't have a problem with it. I can't wait to fly with the PF trim system...I think it is going to be awesome.Originally posted by Zac Weidner View Post
I seriously looked at going to a jackscrew system and it would have been a major modification. Installing a jackscrew tower wouldn't have been terribly hard but designing stabilizer struts that moved with the H-stab was further into the experimental realm than I was willing to go. If you have deep pockets you could buy the PA18 tail struts from Crosswinds and modify it to fit the BH but really I don't think the benefit would be worth the time and cost.
Depending on which model 180/5 you look at the CG envelope is between 11" and 12" the BH has a 12" CG envelope so no difference.
Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.Comment
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I know, I shouldn't be asking a biased crowd these sorts of questions, but I'm assuming at least a few of you have already done all this research.Originally posted by Battson View Post
Is the Super Rebel something I should be looking more into? I wasn't able to find a lot of data on them, so do you happen to know a few of the real specs of this airplane? It appears it's very similar but with a little higher useful load. I just don't know if it will actually do what the "calculated" specs are. I also don't see any for sale or any pricing on their website for the kits, so perhaps that would eliminate it also. The total investment is definitely the deciding factor because I think a nice 540 BH will be at the top of our price range.Comment
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When you say "similar" - I'm not sure which planes you are comparing. The Super Rebel 2500 is a totally different proposition to a Bearhawk. Imagine a different-looking 185 and you've basically understood where the Super Rebel fits in. A larger hp 540 engine, alloy skin, 6 seats, spring gear, etc. Of course the SR2500 owners will tell you about all the subtleties and how they are "totally different" to a 185 (just like all the different models / years of 185 are totally different to each other...err-emm) - but as a potential buyer, the first think you want to know is that they occupy the same operational niche. It's a bigger more expensive aircraft more suited to a heavier hauling mission, operating from nicer airfields, with different maintenance needs.Originally posted by Zac Weidner View PostComment
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I believe the Super Rebel is now known as the Murphy Moose. They show up for sale from time to time. As Battson says, it is a larger, heavier, more expensive aircraft.Originally posted by Zac Weidner View Post
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Yeah, that. The Bearhawk has a very nice, wide CG envelope. The pitch sensitivity can be fixed by changing the operation of the trim tabs.Originally posted by whee View Post
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I've also read since posting about the Murphy that it seems many have not had the best of luck with the factory support while building. And a heavier, more expensive aircraft is not what I'm looking for, so I guess I'll avoid that route. It also appears that 185's in the condition I'm wanting are at least $40,000 out of our price range. A 180 or Bearhawk seem to be my two best options still, and the Bearhawk has the benefit of all new construction and I get to have the satisfaction of flying my own handiwork.
So the CG range is wide on the BH, and I assume the pitch sensitivity hasn't been corrected much by the airfoil shaped horizontal stabilizer. Is there a particular reason AviPro has not corrected the trim tab issue to mirror what a few of you have done to remedy the sensitivity?
By correcting the servo trim tab, does this make it fly hands off more readily, or is it solely an issue of maneuvering better? What I'm getting at is, in cruise, is it somewhat unstable in pitch if you don't keep a constant eye on it?
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The plane flies hands off just fine in most situations. At extreme aft CG loads then it does take constant attention, for lots of guys this isn't a big deal and becomes something you don't even notice. I wouldn't say it is an "issue" that needs to be corrected. It is something I didn't like so I changed it. Bob doesn't mind it so as of a year ago he had no intention of changing it. If I wasn't going to be flying around with 5 people and camping gear at a far aft CG I wouldn't have changed it either.Originally posted by Zac Weidner View Post
Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.Comment
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Most airplanes are pitch sensitive when loaded to aft CG. All the certified planes I have flown were like that. I remember well a few flights with aft CG that got my attention.
Now I will make a comment that some might take offense to but is a fact. There is one BH flying with the trim system modified. The owner likes it. No problem it is his plane and these are homebuilts that we can do what we want with. But of all the builders planning to do this modification - I bet very few (or none) of them has flown the plane with the modified trim system. Something to consider. MarkComment
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What I think you will find is that the sr2500 will have far less support than our Bearhawk. Last years Oshkosh was the first year in several years that they have had a presence at Oshkosh. There is an active user group for the Murphy models. Replacement parts are hard to obtain. Prior to the new model there were no parts made until they have firm commitments for 10 new aircraft. There are also mods that need to be incorporated so that the plane is stronger. As designed it has some week areas that need to be addressed. Done right it is a nice plane. My 2 cents is that a tube and fabric plane will stand up to off airport operations better than a sheet metal aircraft. No lose rivets. Bob's design has proven to be a great compromise.Comment
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What Mark said is absolutely true, I've never flown a BH with the PF trim system and I certainly don't take offense. Most of us will likely never get the chance until we install it on our own airplanes. These statements from Budd Davisson is what made me decide that Pats solution was the one I wanted to follow:
"BH'ers, I just came back from flying Pat Fagan's rehabilitated Smokey Bearhawk and I just want all of you to know that his modification to the trim tab system has made what was a good airplane into one that is as nearly perfect as an airplane ever gets."
"I flew the airplane at the same time that long time BH pilots Kevin Deuscher (spelling?) and Scott Williamson did and we were all wildly enthusiastic about the improved handling."Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.Comment
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Kevin has done the modification on his scratch built. Scott would have liked to but had already progressed beyond the point where it could be readily done. I used to have to remind myself that I was heavy before takeoff and act accordingly with pitch. I no longer have to do that as the plane now flies the same heavy or light.Comment
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So from some of the reports I'm seeing - a Bearhawk with a O-540 is about 10Knots slower then a Cessna 180 with a O-470 (is that what others are seeing) What is the major drag that is slowing the plane up... maybe perhaps with the Bravo that difference would be smaller, maybe 3 knots or so slower then a 180 (assuming same size tires, etc)? Is there anything else that can be cleaned up to gain a few knots. I'm trying to avoid calling my buddies (all 180 guys) and asking them to pull back power and let me catch up. One thing I noticed is the windshield on the bearhawk seams to be at less of angle (not as aerodynamic compared to a 180) - or am I off there? Nothing that can really be done I about that. I guess one could put on something to clean up the landing gear shock strut - I think there is something on Bob's site for the shock strut fairing.
But hey - if with the Bravo Bearhawk ends up being 3-4 Knots slower then a 180... I can live with that - lots of pluses on the Bearhawk side.Comment
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Lots of guys say their 180 is 10kts faster than a Bearhawk.... But when I fly with them they don't seem to be able to pull away at that kind of speed. Maybe their 50 year old instruments aren't so accurate any more. Sure they are often a little faster, but they have tires about 1/3 the size of mine and no VGs installed, so that has to be considered.Originally posted by corefile View Post
My plane is certainly slower than a fast 180 (small tires and no VGs) in a high altitude cruise situation, if we use the same power settings. About 2" MAP slower, to look at it another way, it wouldn't be 10kts, probably more like 5 to 6kts. So I therefore assume they are capable of similar speeds with a similar fit-out (tires / VGs). I think the flying wires and tailwing braces are the key source of drag which differentiates the two designs, those things add drag like nobodies business. I don't think the windscreen is a big deal, the shape is still aerodynamic, it's the total frontal area which counts.
But then again, in different circumstances I have had no trouble keeping up with a slow 180 airframe, and the same for a 185 on 31" bushwheels and with VGs. I was cruising lean of peak at 120kts near sea level on a cold day, and easily able to keep up - maybe their instruments said their aircraft were going a little faster... but I wasn't getting left behind and I was burning a fraction of the fuel they were. We all had a decent load aboard during that formation flight. In fact, in a cruise-climb I was fractionally faster than both those aircraft.
As always in life, the simple rules of thumb don't hold true in every situation.
I would have a Super Cyclone before I had a 180/185Last edited by Battson; 10-31-2016, 05:50 PM.Comment
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You are considering a Bearhawk at a great time as the new 4 place version 2.0 is just about to come out. The new Bearhawk Bravo has the improved handling and greater speed built into it from the lessons learned with the patrol. We finally have our BH 4place running and getting close to final inspection after 12 years. We were told at the outset to go with a kit from a scratch builder and we elected to scratch build. The airplane is a nice piece of work and is one to be proud of. The savings with the QB kit in terms of years is priceless in my opinion and we regret that we did not take the sage advice of experience.
Assembling a kit shaves thousands of hours out of the build and the learning process. I cannot say how many 100's of hours are involved in home schooling one's self for the scratch build process. Building a kit with the knowledge and skills in your family would make this process go a lot faster. For most of us the learning curve is vertical. Stay on the traveled path of other builders when it comes to power plants and stick to the plans. Most common engines with lots of experience are the Lycoming 360's or derivatives, Lycoming 540's and Continental 470's. We went off the path with a Continental IO-360 210hp. It will be good but I know of 2 others with no BH experience to lean on. I had to go to the Cessna 170 forums for advice as this is a regular upgrade with 170's and 172's. It took time to research the idiosyncrasies of the engine, best prop & governor, and a unique engine mount. We mocked up a custom exhaust and had it built and had to modify the two halves of the typical BK nose bowl, I had to create a mock up of the bottom half, made a female mold and then cast the part. It looks great but a lot of hours chewed up walking off the path. We emulated the pressure cowl to get good airflow through the engine, set the exhaust up to have a good clear air exit lane and rounded the lower firewall to make it friendly for the air exit. All the work seems to have paid off as the nose bowl cowl arrangement is clean and it can run with good engine temperatures. The front 2 cylinders run cooler at idle until the throttle is applied. The cylinder temps are all the same with power applied. A lot of thought, attention to details and fingers crossed that the cooling worked, It is an accomplishment but again ground up 100's of hours that could have been avoided following the regular BH power plant choices. It is done and will sip fuel so it will be good to see how it behaves in the long term.
Keep it simple, fabric interior and get it done faster. Sell one of the airplanes to finance the kit and enjoy flying the other until the BH Bravo is ready to fly. To get the build done requires more dedication than procrastination. Those who set their airplane projects on the back burner are the least likely to return to it with the enthusiasm it takes. There will be some days where you would rather be anywhere else but turn the radio on and power through it. Progress fuels the spirit to continue to the next phase. The kit eliminates the tedium of making countless parts, tooling etc.jigs, welding, a small fortune in shipping costs to accumulate materials and parts. With a kit the visual progress is bigger and the progress will be a quantum leap as the way the kit arrives is what all of us scratch builders envy & strive for. The QB kit is an excellent start point. A friend who built a Murphy Rebel was admiring our completed wings. He commented that when you think your are 95% done there is 85% to go go. There was never a more prophetic statement. It is important to maintain work life balance with the Mrs. and kids. Especially the Mrs. as it would be nice to still have her there long after the airplanes and kids are gone.
Consumables. No one ever talks about consumable but scratch built consumables impose a good cost into the project. I have 40 years of project engineering design, construction and management. Consumables on a job are usually in the range of 10%. One of my partners absolutely hates the term now as the consumables would pay for a great all inclusive trip to the Caribbean. What are consumables? Construction tables, sandpaper, sheets of MDF, welding gases, grinding discs, sanding belts, long and short cobalt drill bits, scuff pads, primer, paint, jigs, support frames for wings, nails, screws, miles of masking tape, printer cartridges, solvents, alcohol, silicone and wax remover ad infinitum. Add to the overall costs are years of utilities such as fuel to heat the shop, & years of electrical cost for the shop. We give our partner $1k a year for fuel and electricity and he is likely coming up short being in a colder area.
Tooling specific to the build such as routers, router bits, grinders, welding equipment, rivet squeezers, large c frame for dimpling, dozens of clamps, hundreds of clecoes, cleco pliers, temporary spray booth. Avoiding the majority of the cost of the consumables, a lot of tooling and a pile of shipping would pay for half of a quick build wing. The consumables in a project are a dead loss. In hindsight consumables are hard to ignore. The definition of experience is something one has when they are finished that they could have really used when they started.
If one assigns half the consumable cost to the wing with shipping and some tools at $5k, wing materials around $4k and 3 -4 years of shop utility costs at $3k that totals about $13k. The wing kit is $19k so that leaves $6k for labor. Eric Newtons log gives 1225 hours to complete the wings. So to be kinder & keep the math simple lets say 1000 hours that means a person's time is less than $6/hr. Newton took 1225 hours to scratch build a pair of wings and 111 hours to complete the patrols QB wings. The difference is 1114 hours or a half year of labour savings based on a 40 hr work week. The same thinking would apply to the fuselage. It gives thought as to how many hours of ones regular work went into paying for the scratch built consumables, utilities and shipping costs that add no value to the airplane.
This is not to be negative but to show the advantage of a quick build kit to get flying sooner with little difference in final costs. There was an article years ago in the Beartracks of an AME completing a quick build kit in less than a year. He would have dedicated a good deal of time in a short window. His advantage is that he had the skills to charge through the project while most of us are learning on the fly. You have the skillset to get completed quickly and the ability to keep costs down.
Glenn
BH727Last edited by Glenn Patterson; 11-13-2016, 02:35 AM.Comment
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