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We are doing fairings around the gear & horizontal stabilizer. We are getting set to mount the wings in the next 2 or 3 weeks when hangar space is available. A lot of work to get here.
Glenn
BH727
Glenn
BH727
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Glenn, I've been waiting and waiting to see your TCM IO360 bird fly!😀 I hope it performs as good as it looks. I think we need to see a pic of what's under the cowl.Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.Comment
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Hi.
I am with you on really wanting to see this fly. I really want to alert you to the tight fit of the nose bowl. I will get you some pictures when we have the covers off again. My friend watched a Maule take off with little run way and go straight up. It turned out that it was the TCM IO-360. There is a Stinson that has the same engine and it takes off quick on wheel & floats. There are a couple bush planes flying here with the TCM IO-360’s that the owners love. We have been told that these engines from a couple sources that these engines will cruise on 8 - 8.5 gph.
We are using the McCauley CS prop & governor commonly used on Cessna 180's & 182's trimmed to 82 inches. We did a lot of research to come up with the prop for this engine. Referenced STC's for upgrading Cessna 170 & 172's, Stinson 108's etc. & Maule installations. Most use an 80 inch but some 82 so we are starting with 82 and if it is too much then we can have it trimmed. These McCauley props are long and they can trim down to 78 depending on the aircraft that uses it which makes it friendly for our applications. We worked with Aircraft Exhaust in North Dakota to build a clean SS header system as the old 337 exhaust could not be repurposed. It might give 5 or 6hp more. It looks sharp & is out of the way. We used a Cessna 337 rear engine mount & modified it with Bob Barrows design input to mount it to the BH firewall. The bed mount frame comes close to the front of the engine so that brought some challenges. We used the MC-3A Pitts type nose bowl commonly used on Bearhawks and when it was mounted we had 3/8†clearance behind the spinner. At first we thought it was not even going to fit but was relieved when it came together. The bed mount comes up close to the front of the engine & interfered with the fit up of the nose bowl. The nosebowl was modified to give it a more square chin. I made a template of the lower half & used the template to mock the bottom half of the nosebowl. I used bondo to profile the new shape & worked hard to make both sides symmetrical. Once I was satisfied then I put Meguirs gold car wax on the nose bowl & laid up fiberglass on it to create a female mould of the bottom half of the nosebowl. Then I laid strips of 1†cushion foam on then put a couple layers of glass on to form stiffener ribs to hold the mold shape. I pulled the female mold off & then waxed the mold to use to form the lower chin. I did everything I could to keep the nose bowl tight as possible to the front of the engine. I did not have the prop & spinner on to check the measurements so I won the lottery when it fit.
The top of the nosebowl was an exercise in frustration as well. I pie cut it and made it symmetrical because it was not the same left to tight. I also stretched it up slightly so that the upper cowl stiffeners cleared the air cleaner. There are 3 tight points. Chin, air cleaner & line out of fuel pump up. Lots of room behind the engine. The engine came with 337 baffling that we used for engine patterns and made new on the top. We adjusted the front of the engine baffles to seal against the new nosebowl.
My partner wanted a flat clean lower cowl with a good slope to it as that was a common feature on some high performance STOL aircraft that he liked. The TCM IO-360 makes for a clean chin without the air intake box.
Our engine is 24V so we left it that way & bought 24V powered equipment. The Cessna 337 that was the engine donor had a complex alternator control for the dual engine so we sought technical assistance and put in a simple alternator control with a built in over voltage regulator. The battery is located under the passenger seat.
Here are a couple shots but I can do more.
Also we used the Skybolt SK40S5-SET1 fasteners for the cowl which were an easy install & exceeded our expectations. They are adjustable so we mocked up the thickness with scraps of aluminum to adjust the parts prior to install. They went in easy & fit tight. We did not have to go back and tune the fit.
I can give you more information if you have questions on this engine arrangement. I have attached a couple engine photos of the underside for a teaser.Comment
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Looks great Glenn! I like that exhaust! I'm trying to reuse the Cessna XP exhaust that came with our engine. Looks like our engine mounts came out really similar. I will also be using a 82" C203 prop. I have test fit the nose bowl that came with our project and it appears that it will fit with only minor tweaking.
Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.Comment
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I noticed reading through my comments that I raised the top of our nose bowl flange 5/8"' at the top so cowl cleared the throttle body. It depends how the stiffeners are placed that hold the top of the cowl with relation to the throttle body & the air filter. We had the complete engine in place so it helped in with the fit at the tight points. I remember looking at the lever on the air box vacuum breaker as we thought it might need the shaft shortened to lower the spring lever arm. If you can have the complete engine in place when buiding the firewall forward it will help get the clearances. It was high anxiety when it looked like the nosebowl was going to mesh with the spinner. As luck had it that it cleared the spinner by 3/8". We had to do some adjustments on the baffle & trim the inlets. The nose bowl cooling inlets were ducted up to the front engine baffles to try to reduce the inlet turbulence & increase cowl pressure. I narrowed the cooling inlets to allow the fuel line up to the throttle body to tuck inside the nose bowl. The fuel line was a close fit when it was done. The nose bowl was split and that made it work for assembling & disassembling of the cowl. The cowl & nose bowl need to be off to get the prop flange bolts and spinner backing plate. The tear drop corner corner was installed along the square edge of the firewall at the cooling outlet to make the air exit better at the corner by eliminating the turbulence of a sharp corner.
GlennLast edited by Glenn Patterson; 04-24-2016, 11:10 PM.
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We are using the 82" C203 as well. The nose bowl with your kit looks Continental friendly. I spent more time than I wanted to to make the MC-3A bowl work. Basically created a new bottom half & modified the top so that it is no longer an MC-3A. I would have happily sourced one that would fit rather than put the hours in I did. I mentally set a dollar rate in my head that drives buy or build. If I had done that on day one then I would have gone the kit route. You made a good decision going the kit route.
It is the position of the fuel pump & lines that is a restriction and limits the nose set back. The Cessna XP exhaust is a better deal than the Cessna 337 exhaust. The arrangement of the front and rear engines are completely different. My partner is an excellent TIG welder that could have built an exhaust but I bought the exhaust to expedite the build. You have made a wise move acquiring a kit. Our instrument panel is the Dynon D180 with the 6 cylinder Continental package. It monitors all 6 cylinders. We have a very basic panel with the Dynon, Garmin GTR200 radio & a transponder. A tight clearance was the air cleaner so we installed a Brackett Aero Filter BA24 which is the correct filter for the engine & it was smaller than the one that came with the engine. Our local aircraft maintenance company flies 19 Cessna 337's for forest fire watch along with a number of Aerocommanders. They showed us the smaller filter that was an update of the version on our engine. They said that the Cessna 337 engines are tough and normally require routine maintenance. They spend most of their energy on the Aero Commanders.
You will have great airplane when you are finished.
Glenn
BH727Comment
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Nothing representing substantial MVP this weekend, but a lot of little things completed. Got everything drilled and trimmed for attach angles and stiffeners.
It sure would have taken a ton less time if I had done it Glenn's way, but hindsight is 20/20. But progress is progress, right?
Hopefully getting spar fittings started this week.
Sent from my iPhone using TapatalkChristopher Owens
Bearhawk 4-Place Scratch Built, Plans 991
Bearhawk Patrol Scratch Built, Plans P313
Germantown, Wisconsin, USAComment
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I guess it isn't something I did today, but I try to stay off of the computer on building days, and it is the most recent thing I've done to the plane. I added a provision to run some cooling air to the avionics, to see if a problem that I've been having is related to a lack of cooling air. Details are here: http://bearhawkblue.com/avionics-coo...resh-air-vent/
The short version is that I though up a simple way to tee a 3/4" duct off of the existing 2" duct, with the help of my aluminum-welding friend Alan Waters.Comment
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I stitched an aileron! Understand, it's been over 20 years since I've done fabric work. To top that, I never stitched anything. Only used screws. Because I was never Cub Scout or Boy Scout, I'm terribly knot challenged... While enjoying one of our frequent 'old pilot's lunches', a friend suggested the Staggerwing Knot: https://m.youtube.com/watch?v=9OsIBk_RWQY
After watching that video several times, I built a practice frame and stitched it, about a half dozen times. Today, I did the real thing and it looks great.
Two observations: Superflite system is more forgiving than the Stits process. Staggerwing Knot is easier, for clutzes, like me.
I've only begun covering the Patrol, so I'll get a bunch of practice!
Onward!
BillComment
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Worked finishing up the door handles/latches. Will have them done tonight I hope.
My engine choice has been on my mind lately and I think that triggered the dream I had last night. Dreamt I built myself a Pponk (O470 with IO520 cylinders, 285hp) but I did it a bit different. Instead of IO520 cylinders I used GTSIO520 cylinders so I still had downdraft induction and I kept the fuel injection. It was awesome.
Anyways, it's nice to be back working on the plane.Last edited by whee; 05-26-2016, 05:02 PM.Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.Comment
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Sorry, I usually check the forum via tapatalk and these comments don't show up there.
My dad found the handle at the local truck accessory shop. I can't remember if they are off a ARE or a Leer topper. I used the same style hinge Bob shows in the plans but I made them with bigger and more sections. I don't have any better pics but if there is something you want to see let me know.
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Today, I put the joggles in all my center ribs. 90 mins a day is my goal.Comment
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Covering. Still covering the little surfaces, no fuselage yet. Stuff keeps getting in the way of things I need to do! The more Surfaces I do, the more I remember why covering is fun. Just have the elevators left, before the fuselage, though.
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This gallery has 1 photos.Comment
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Installed the Steen supplied streamline tail wires on Patrol. Had to cut 1 inch off the end of all four wires with the most threads and a half inch off the other end (one end had about a half inch more threads than the other) then they fit perfectly. They thread in past the witness hole in the clevis but still have plenty of adjustment.Comment
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Since my lil co-pilot arrived there hasn't been much progress other than finding our new house! Move out of our temporary employer sourced accommodation next week... no more building in a 1 car garage!Steve Nicholson
Lafayette, LA
4 Place Scratch build #1377 in progress (Wings)Comment
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Created spar attach plates and splice plate master routing patterns.
Sent from my iPhone using TapatalkChristopher Owens
Bearhawk 4-Place Scratch Built, Plans 991
Bearhawk Patrol Scratch Built, Plans P313
Germantown, Wisconsin, USAComment
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