We got the 3" numbers put on the rudder and for a quick look set it up on the vertical stab.



I like how the solid control surface color contrasts with the fuselage, as I had hoped.



Spent a while getting the control cables for prop, throttle, and mixture run through the firewall. A little work here building a custom attach bracket for the cables on the engine oil sump, and getting them adjusted for play.

Looks like we are getting closer to flying this thing!

[quote="A1Skinner"]Very nice! That is going to look great. Are the tops of the wings going to he solid blue?

Thanks!

We are planning on painting the wings predominantly white, with the leading edges being painted blue (not sure how far back from the leading edge yet). This is the plan, but could change. Frost being the main concern with the color white.

So now the wings are painted , and the paint booth is removed from the shop so we have lots of extra room we need to do the fuel flow test.





Plan now is to install the wings temporarily, hang the plane and put a bit of fuel in the tanks to verify our fuel flow rates to the carb at different attack angles, then its off to the airport for assembly.

We have completed our fuel system testing! Our understanding is that while its not technically required, we felt more comfortable verifying prior to first takeoff that we had ample fuel flow to our O540.

So we installed the wings temporarily:



And rigged up a fuel can and timer to document fuel flow, we were using a postal scale to weigh the amount of fuel and converting to come up with a volume amount.



We then set the fuselage at an 18 degree climb angle, with 4 gallons of fuel in either main tank. This was what we considered a bare minimum fuel level in the tanks, at this attitude we "just" began to see fuel level in our fuel level gauges.

After our first test, we found we were getting much less than we had initially anticipated. Using the FAA approved calculation based on BHP of the engine, we required 32 gallons/hr fuel flow for our Lycoming O540 fuel system and were getting much less than that with the electric pump. Something didn't seem right with the electric pump, and we started to suspect that it was faulty after checking over the rest of the fuel system. After scratching our head for a while, we determined that the pump we had been sent was a 24V pump instead of the required 12V version (they look the same). We then isolated the pump electrically and rigged up a 24V DC power supply, and tested again.

Our second test with the pump properly supplied with DC and 3.5 gallons in either tank (fuel selector on "both") was 36 Gallons an hour! Muy Bueno!

So that made us feel confident that we had more than enough fuel supply in any situation we could foresee. We took the wings off, ordered the correct 12v pump, and installed it. We are headed to the airport this next week!

Looking great! It has to be so awesome to see things coming to completion. Wise choice on performing the flow test. I've been told that some DARs will not issue certificates unless a fuel flow test has been performed.

I thought that O540 installations didn't require an electric fuel pump. Is adding one something that you guys decided you wanted? Only for takeoff?

Very exciting indeed. I'm still welding on my fuselage and building my engine, feels like things are moving at a snail's pace.

Is that the old style gear I see with the lower former on the trailing edge? I'm about to modify mine to allow for big bushwheels, and I'm trying to figure out the best shape.

Thanks guys, happy to be able to share our experiences and hopefully help give some motivation to others that are building planes of their own!

So your right, we too have heard from some sources that gravity feed would be acceptable for a 540. We are by no means experts and we always try to err on the safe side of what we know... so take this for what its worth...

After researching and looking at other aircraft such as the Maule, we chose to give ourselves the added capacity of the standard type mechanical pump on the engine accessory case and with that, a backup DC pump. So during the test, we were really giving our "backup" DC pump a try and verifying for ourselves what our system was capable of supplying. (Trust but verify)

For a certified aircraft, I believe the FAA would be "happy" with 125% of maximum fuel needs during testing with a mechanical pump, and gravity feed 150%. After calculating 125% of needed supply for 260 BHP we came to a 32gph "certified" amount. We didn't feel this was obtainable without supplementary means with 3/8" versatube (the tubing we used), judging by writeups by others that had done fuel testing.

An example referencing an O360 Bearhawk (180Hp) Gravity feed of course:

http://mybearhawk.com/finish/fuelflow.html

Our information shows a 260HP O540 uses 25.3 GPH at sea level on takeoff as per the engine operators manual, so we got a "certified aircraft" flow number of 31.625 GPH needed (with a mechanical pump) and 37.95 GPH without. This number is for sure very generous, but gives us a large safety margin and the knowledge that 260hp is gonna be there whenever we need it regardless as long as there is fuel left to pump.

A great writeup on the subject from Russ Erb relevant to the 260HP O540:

http://www.eaa1000.av.org/pix/erbpix/re ... elflow.pdf

I'm not familiar with the newer style landing gear, I know our kit was built sometime around 2005-6. If I remember right, it didn't look like it would be hard to remove the former on the gear..

And yes, its a great feeling to finally be headed to the airport with a plane to fly again!

How long did it take you to build it?

The plane looks great. I like the way you've added chafe and wear tapes before flying it. Good move, wish I'd known to do that.

You'll be so pleased to be seeing clear skies through the windows in future. Flying the machine you've built is a dream come true.

Sounds like you've installed enough fuel pumps to use Bendix fuel injection in future, if you so desired. A nice option to have if you want an extra 10 horsepower or want to remove carb ice risk some day!

TxAgfisher wrote:How long did it take you to build it?

An AviPro Bearhawk kit will cost in excess of $40k (no engine, prop, avionics, paint, etc) and take an ambitious 2 to 3 years to build at best. I looked into doing this before it became evident the Maule would get us going a lot faster and cheaper. I still would like to build someday which is why it is great to see what these guys are doing with theirs.

Thanks guys!

My first log entry was in Aug of 2008, so we are rounding on 9 years for us. That amount of time is somewhat misleading because we made changes to things (Doors/skylight/added many nutplates and access points for maintenance/etc..) outside of what the plans called for, and spent a good 6 months or more working on fabricating a set of new rigging/spreaders including rear float attach points for our EDO 2870 floats during that time. Another big drag on progress is shipping to a place like Alaska, no 2 day free shipping here. Purchasing an engine would save considerable time as well.

Also, we haven't let building get in the way of family stuff (much).

Battson - Thanks for the encouragement! I've studied your article in Beartracks and here at BackcountryPilot, and watched most if not all of your Bearhawk youtube videos - they have helped bridge the time till we get ours in the air! Thanks! Someday I plan on making a commerical trip to New Zealand what a beautiful place! I have a close friend that has spent months touring around your area and he had nothing but good things to say about how nice everyone was!

DeltaRomeo - Smart move on buying certified because of cheaper/faster!

HawkRT wrote:Someday I plan on making a commerical trip to New Zealand what a beautiful place!

Be sure to send me a message when do you. I'll make sure you get a change to do some backcountry flying in our Bearhawk, at least. If you like fishing or hunting, so much the better!

DeltaRomeo wrote:

TxAgfisher wrote:How long did it take you to build it?

An AviPro Bearhawk kit will cost in excess of $40k (no engine, prop, avionics, paint, etc) and take an ambitious 2 to 3 years to build at best. I looked into doing this before it became evident the Maule would get us going a lot faster and cheaper. I still would like to build someday which is why it is great to see what these guys are doing with theirs.

Yes, that is the most common situation, and 5 or 10 year builds are common too.
Although I would say most two seater kits run you between $45k to $60k... so I don't think the Bearhawk is expensive within it's market.

I got my kit for less by catching a sale, and built it over 18 months The last 3rd of the build was hellishly tiring, but it was also over quickly. Like ripping off an 18 month bandaid. We also did a lot of mods like 134RT, so it could be done even quicker by a dedicated individual.
On the other hand, building my own plane was also one of the best things I've ever experienced, and derived the most enjoyment from apart from family and friends. Once you are done, it is so worth it.
My point is, don't be put off too easily.

Looks good, I see you did all the right float mods like lifting points, extra cooling vents in the cowling, seaplane door, etc. I've been flying mine on floats a bunch this year and having a blast.

Battson wrote:

HawkRT wrote:Someday I plan on making a commerical trip to New Zealand what a beautiful place!

Be sure to send me a message when do you. I'll make sure you get a change to do some backcountry flying in our Bearhawk, at least. If you like fishing or hunting, so much the better!

Thank you Battson!

I totally agree with you, I really have enjoyed working on our project over the years - In reality we are getting close to the end of the marathon for us and although its already well "worth it" to us - things will look totally different when we fly it for the first time. I was lucky to work with my father who has a wealth of knowledge when it comes to many things, especially aircraft. So a big part of the build from my perspective was getting to spend those years with him building, and getting a chance to learn how to use all those cool airplane tools!

Not at all trying to be discouraging to the hopeful, just being as honest as possible about what it took us!

Bhawk wrote:Looks good, I see you did all the right float mods like lifting points, extra cooling vents in the cowling, seaplane door, etc. I've been flying mine on floats a bunch this year and having a blast.

Thanks BHawk, glad to hear of another Bearhawk on floats! What model float are you using? If you have any pictures handy of your float install you'd be willing to share I would love to see them!

My father and I sold our smaller airplanes (C150 and BC12D) to build our Bearhawk together, and I have yet to get my SES rating. He tells me "I wont go back" once I've been PIC in a float equipped plane!

I'll have to look when I get home from work for some pictures of our float rebuild/install. We purchased an early set of EDO 2870 floats that were serviceable, and tore them down about 4 years ago.

We replaced the spreader bars with new "oval shaped" material, made/installed new front bumpers/paddle pocket/splash rails. I took the rudders completely apart and sandblasted everything and we epoxy painted them. Replaced all cabling with new stainless cable and barrels, and machined new rubber parts such as the rudder stops. We relocated the pump-outs to the side of the floats (these are "round top" type EDOs), sandblasted all the hatch covers and painted, built and installed storage hatches in the center most bulkhead segment.

Then we spent a considerable amount of work/time actually filling the floats with water and marking leaks to be repaired. This ended up being somewhat of a diversion, we needed to perform the angularity checks and fab work to get them installed on the fuselage prior to covering but it ended up costing us quite a bit of progress time towards finishing the fuselage on wheels.

Since floats were a main consideration in the design and build of our project, the 540 Lycoming was the engine of choice. Otherwise we both agree a O360 180hp would have been a great (economical) choice.

Here's my set up. The floats are 3000 series made for experimental planes in Canada. It's overfloated but the price was right and they were in good shape. They really aren't that much bigger than 2870's, I know because I've measured and compared the two. There's a few more pictures in my photo gallery of it.

The method I used for mounting them was to find the cg of the floats and align that with the Mid point of the cg range on the airplane. Then give about a 3.5 degree angle of attack from the bottom of the wing to the top of the floats. This should give you about a 4 degree or so aoa with the cord line to the floats. It now burns around 2 gph more to go the same speeds that I used on wheels. I usually fly 100-110 mph at 2,000 ft and burn around 10 gph.

I don't know what they weigh exactly but my empty weight went from around 1370 on wheels to around 1640 on floats.

Hope this helps.

DeltaRomeo wrote:

TxAgfisher wrote:How long did it take you to build it?

An AviPro Bearhawk kit will cost in excess of $40k (no engine, prop, avionics, paint, etc) and take an ambitious 2 to 3 years to build at best. I looked into doing this before it became evident the Maule would get us going a lot faster and cheaper. I still would like to build someday which is why it is great to see what these guys are doing with theirs.

I am familiar, I spent some time with Mark poking around and even flew his Patrol. That's part of why I sold my Maule, getting into a Pacer and hopefully starting on a BH in the next year.

Seems like Battson is the exception - I am hoping to follow suit!