4-Place Information

[Zac Weidner]

Hello all,

I am new to this forum and Bearhawks in general. A quick biography to introduce myself; I'm from southern IL and live and fly from the family farm here on grass. I currently fly a Tri-Pacer and a Twin-Comanche, and I am not entirely familiar with Experimental aircraft or especially Bearhawks, so please forgive my ignorance(s).
I attend AirVenture every year, but my father and I have decided lately that we should consider some alternatives to our two current aircraft, so I was out browsing around last week, and came across the 4-place Bearhawk. We're trying to find something that would replace the two airplanes and be a good compromise for them. We spoke fairly extensively with Mark at the tent about this aircraft and some details, but I have several more questions in my search of different options. We're going to either have to spend a significant amount of money on our Twinco to get it back into good shape, or trade for something else. It needs engine and prop overhauls, a complete panel upgrade, and probably an autopilot or lots of expensive repairs to the Altimatic III.
I'm very keen on the idea of how much more affordable most parts seem to be for Experimental vs. Certified aircraft, especially the avionics.

I talked to two different companies at AirVenture about our options, and I came up with $25-35K for an awesome Garmin IFR panel and autopilot in an experimental, just FYI.


Now for the mission objective I'll be looking for out of our future aircraft: I want to be able to carry 4 passengers and 200# of baggage with the option of 5 passengers/less baggage with at least 5 hours of fuel, and have as fast of an airplane as practical. 95% of the flying will be in the Midwest on normal/long runways. So I don't care too much about awesome climb or super short takeoff/landings. I'm also open to other (affordable) aircraft suggestions, even though I know you're probably all partial to Bearhawks and Experimental. We restored the Tri-Pacer and won a Lindy at Airventure 2010, so the build should be no problem for us I believe.

I'm trying to decide on the engine model and prop combination that would suit us best, and what it's really going to cost to go this route, so any advice and actual figures are MUCH appreciated here. I'm leaning towards an IO-540 with 3 blade 62" Catto Prop.

I talked to Craig at Catto Propellers about this aircraft possibility, and I was quite surprised by his comments. He said that I would likely be happier with a fixed pitch cruise prop than I would be with a C/S prop. I'm a fan of the much lower cost, but I don't want to be disappointed with the performance. Although I'm much more concerned about cruise speed than I am with takeoff distance. And I really like the potential weight savings of a composite fixed pitch. He quoted 3,600 for 3 blade fixed pitch, and around 19,000 for C/S 3 blade! I'm curious what others have paid for a Hartzell C/S with the discount through Bearhawk?
Also, could someone provide me with some close numbers as to what I could expect with a cruise prop on the different HP options when cruising at 65-75% power and using the new "B" model wing?

What are some real life empty weights from you that have built a similarly equipped aircraft?

I would also like to hear some fuel flow figures from the different engines at 65-75% power. I'm planning to install an electronic ignition to increase efficiency, so please take that into account.

Last but not least, if you're not already overwhelmed with all of these questions, I'd appreciate any other tips and advice for a potential new owner of this aircraft.

Thank you in advance,

Zac Weidner

[jaredyates]

Here are some unscientific trends for empty weight. A light 4-cylinder with an electrical system may be 1200-1300 empty. Add 100 pounds for a 540 if that's all you add, but often bigger engines also come with aux tanks and other amenities. More common 540 weights are 1400-1500, with the outliers being 1300-1750. A 6-cylinder airplane with a fit and finish in par with a store-bought airplane is likely 1500+. If cruise speed is your priority above takeoff and climb, I'd be concerned that you might not make use if the real strengths of the BH. Are you also comparing the RV-10 or Sportsman? Those tend to be faster, but less capable in other ways. Mark's plane has always been one of the faster ones, so with the new wing already installed he'll have the most favorable cruise numbers.

The fuel flow at 65% power on a 360 is around 8 gph, and in our BH that yields around 100 knots indicated. For some reason ours is on the slow end of the scale. In theory, a 540 burning 8 gph should produce the same cruise speed, but I can't tell you what the 540 burn or TAS would be at 65%. There are others who can provide better data.

[Battson]

540 TAS at 65% with small tires would be 125-130 kts, possibly a little more. I see 120-125 KTAS at 65% with 31" tires

[whee]

I can't anwser most of your questions but...

A 5th seat takes up all the baggage in a BH. A light weight fixed pitch prop will make it so you will reach aft CG before you reach gross weight. If you don't care about STOL or climb then Craig will be able to set you up with a prop that will work for good cruise speed but to me that's like having a single speed sports car. There are faster airplanes that meet your requirements. If you want to fly IFR you'll probly want autopilot.

If if I could afford to operate a tripacer and a twin Comanche but wanted to sell them and buy one airplane it would be a Cessna 180H.

[Zac Weidner]

So, it sound like I could easily be down to a 600# payload if I have an O-540 with aux tanks and an IFR panel and autopilot. In that case, I'm not getting the performance I was looking for. I'm wanting something that will carry 4 people with bags and full fuel at 130+ knots. The Sportsman doesn't seem as capable, and the RV-10 is about the same useful load, if not a little lower, except at almost double the cost for comparably equipped aircraft. If I have to spend much after trading 2 for 1, I'm much better off to spend the bucks on the Twinco and have the best of both worlds.

I'm wondering why there wasn't a gross weight increase with the new, longer wing? The Wing-X mod on Cessnas adds something like 500 lbs. GW. I believe it is more wing extension than the BH was extended, however.
Is GW something that is determined exclusively by the kit manufacturer, or is there the option to set your own GW when building? Like I said, I'm basically new to the Experimental world because I've never paid much attention to them.

Another thought here in regards to GW; Is it not possible to set the GW to basically any reasonable figure as the builder? I understand that this airframe is tested up to 6.6 G's at 2,500 lbs., so couldn't one be safe to certify it at, say, 2,800 lbs. and limit it to 5.8 G's (just some rough math)? Or maybe it has to be either Normal Category (4.4) or Utility Category (6.6)?

[jaredyates]

Who wouldn't want to have a single plane with the speed of the fastest, the payload of the best hauler, and the cost of the cheapest, right?
The weight numbers are specified by the designer, Bob Barrows. For deciding on your own max gross weight, as one FAA inspector in our area is fond of saying, "It's your experiment..." In my case, I like to think that my role as builder is to make the airframe match Bob's design as much as possible (at least on the important parts), so I go with his numbers. The experimental rules give you lots of freedom, but as it is said, to whom much is given, much is expected. Personal responsibility and good risk management are prerequisites to safe operation, and it's obviously prudent to value these over stretching the mission. To answer more specifically your question about the new wing and a weight increase, I have heard it said that Bob's max weight is related to the landing gear structure rather than the wing strength, but don't let me be in a position for speaking for him. He's really the one to ask about such things.

[whee]

You can set the max takeoff weight to 2700lbs and you'd have about 800lbs useful after full fuel. 5 hrs of fuel plus reserve, 130kts+ and over 1100lbs useful is a pretty tall order for a fixed gear airplane. I don't know how fast a 540 BH is when burning 12gph with small tires on, 135mph? A BH is a fantastic airplane and I can't wait to be flying my own but isn't a go fast airplane. It is the best all around experimental airplane I could find.

[Battson]

Would be closer to 135 kts than 135 mph - probably around 130 kts I would expect

[whee]

You'd know Jono. I was just extrapolating based on my experience in the BH I flew and the numbers I've seen Blackrock post...but both of those are "dirty" airplanes.

[Chris In Milwaukee]

Just as a point of reference, the Utility Category is +4.4/-2.2g. Typically, there is a 1.5 factor of safety built into the design (FAR Part 23 talks about it), which is where the 6.6g comes from. It basically says that at 4.4g, the structure may permanently deform (not snap back), but not catastrophically fail, giving you the ability to get on the ground safely. 6.6g is the catastrophic failure point of the Utility category. So there is some wiggle room is you subtract from the FoS, but like a fuel reserve, it isn't meant as "extra capacity". As jaredyates said, be safe and conservative with your numbers. The BH has been okay'ed to 2700 pounds takeoff (2500 pounds landing), and that adds some value.

If you truly need 4/5 passengers with up to 200# cargo capacity at 135 knots, you may be better off with a retractable Saratoga.

Thanks for telling us about you and your flying wishes! I hope you can find a way to make the Bearhawk work for you!

[corefile]

I'm not sure you are gonna get the speed you are looking for and you are pushing the limits on the useful load... A Cessna 206 would be another plane to look at - based on what you described as your use case...

[EricP]

I think adding the 5th seat is pushing it for the Bearhawk unless this is just an "add-in" seat for quick rides for little kids. If you are thinking that the 5th seat will be used on a regular basis on long flights with baggage in a plane with an O-540 then I think it is pushing it.

All aircraft are a set of compromises (ask any aircraft designer!) and the Bearhawk has it's own set of strengths and weaknesses. It can easily carry 4 and operate out of short and rough strips. It has great baggage capability and a nice number of big doors. It is not super fast at cruise although it does very well against other aircraft with it's capability. Seating 5 should only be when adding a kid (grandchild seat) in back. Certainly not for long trips or adults in my opinion.

At any rate the numbers don't really work out for what you are asking. Putting the O-540 in will increase the empty weight. It will possibly make the plane faster but you are using up more useful load just by using the larger engine. Then the bigger engine will use more fuel. Yeah, I know you can pull it back but you said you wanted the fastest speed so that is a higher fuel burn. So figure on about 13 gal/hr or so. That means you need to add the extended ranges tanks which means more weight. You now have 72 gal tanks instead of 50 but you have added another 132 lbs of fuel (and the cost/weight of the extended tanks!).

If you could accept the Bearhawk with only 4 seats (or the 5th seat being a tiny jumpseat only) and not have to go with the biggest engine I think you could get the capability you want. Adding the bigger engine actually takes away carrying capability. I suggest the Bearhawk with the Lycoming IO-390 could be a great compromise for you. It would help keep the weight down while giving you decent power and fuel burns.

I guess it would help to know how heavy you actually anticipate your regular 4 or 5 passengers are and when you say 5 hrs. of fuel is that 5 hrs. of cruise or 5 hrs. to flame out? The scenario you are asking about it right at the ragged edge of what a Bearhawk will do in my opinion. I don't want to encourage you do do something that gives you too little margin of safety.

We don't have our Bearhawk flying yet but I am basing these numbers off other aircraft flown and lots of talking and reading (and figuring) about Bearhawks. We have a Lycoming IO-360 and plan on only 4 seats. We have just the regular 50 gal tanks. So we have more than enough capability and trade-off for weight and balance. I only plan on flying about 3 hrs. before landing so the 50 gal. tanks will be more than enough even if we use a 10 gal per hr burn.

[whee]

EricP makes some good points but I just want to say I think the BH will do everything Zac is asking except the speed. My BH will have 5 seats, 52 gallons of fuel, ~1300lbs useful load and about a 125mph cruise on 10gph. By building my own rear seating I've made it so I can seat 5 people in reasonable comfort, my 5'3" wife can sit in my mocked up 5th seat and be comfortable, but there is no room for baggage in the plane. I'll be building a belly pod capable of holding a couple hundred pounds of cargo. Because of the landing gear struts the pod can't be placed as far forward as would be ideal so CG is my main concern.

Like EricP said, operating like this is right on the edge of the BHs capability but I think it can do it. If I didn't mind buying and selling airplanes I would have gone a different route and built a BH later in life but I HATE buying and selling stuff. I wanted a forever airplane that would get the job done now and not be bigger than I want when the kids are gone. For me the BH fits the bill.

[Zac Weidner]

I did not realize that the takeoff weight was 2,700 with a landing weight of 2,500. That makes it much more realistic and useful. I was understanding a 2,700 pound gross only on floats. When I mentioned the 5th seat, I was not talking about using it for cross country flying. I realize that it would not be comfortable and there would be no window for that passenger, so it would have to be for an hour or two flights or less. It would just be nice to be able to stick that seat in if the need arrives.
So now I would like some hypothetical advice; could I realistically build a 4-Place BH, with a IO-540 (400 lbs.) and composite prop (14 lbs.) with aux. tanks to under 1,500 lbs. empty weight, that will cruise at altitude (8-10K ft.) and do 160 MPH or better with 75% power? I will be using electronic ignition, which should help a little with weight and fuel economy. The panel I am planning on would weigh approximately 40 lbs., according to the company I talked to at OSH. I'd be planning on painted fabric for the interior with some nice but lightweight cloth seats and carpet.
I would be very pleased with these figures if I could be fairly certain I could attain them in the real world. I realize that there would still be many variables involved, but I would also plan on keeping the project on a pretty strict diet while building. I might even add a magnesium sump and accessory case to drop some more weight.

I really appreciate all of the advice you all have given me already. I can tell that this is a very lively and supportive group.

[Mark Goldberg]

Hello Zac. I still feel bad you and your father could not fly when you had the chance after the spark plugs loaded up on my BH. One plug had a lot of gunk in the bottom of it and the fine wire electrode shorted out with gunk as well. But after cleaning the engine ran fine. If you had flown my plane you would have been able to put everyone's comments in context.

Your parameters above are achievable with perhaps the exception of the 160 mph cruise. My Bearhawk is doing close to that now at 2400 RPM/23 inches burning 13 GPH. But there is variation in homebuilts as Jared said. I think you could reliably expect 150 mph+ with the possibility of getting close to that 160 MPH. The Model B with the new wing does seem to help speed a little. On the return leg from Oshkosh Wayne reported 158 mph TAS at the 2400/23 setting at best performance altitudes. I normally fly at 2300 RPM/22 inches burning 11.5 GPH or so. On the way home this setting produced a cruise in the low 150's TAS.

About empty weight - Bob Barrows O540 powered Bearhawk (Proto II) had a weight of 1340 lbs with a starter and metal C/S prop. However, NO ONE builds as light as Bob. The lowest weights for a 540 powered plane that builders are seeing is 1425-1450 lbs. Two I can think of in this range built from our QB kits. However most 540 powered planes are in the 1500-1525 range. Mine is 1512 now. What would YOUR empty weight come in at?? It is in your control to a large degree. Building light is a mentality that has to be maintained all through your build. If you look at Bob's planes - all of them - you will not see a bolt with more than 1 or 2 threads showing. You don't find the heavy washers. All light ones. He uses the miniature nutplates that are a little harder to work with because they weigh less. These are just examples of what it takes to come in as light as possible. Everyone wants to, but few are as determined to accomplish this as Bob. The weight is not saved in big chunks. But in a gram or two at a time.

This forum is a good source for info for sure. And I can give you my 2 cents worth in private as well. Good luck, and I hope your future has a Bearhawk in it. Mark

[Peter Bishton]

Mark
Would it be possible when you get a chance to post some photos on your website under the 4 place tab with the changes to the airfoil on the horizontal stabiliser and tailwheel etc so we can see the new work. It sounds like the Bravo is a true success - well done
Peter
# 1134 plans 4 place

[whee]

Check out this thread for empty weights: http://bearhawkforums.com/forum/bear...ata-collection

[Glenn Patterson]

We registered our BH 4 place at 2700 lbs for floats. I was a Spring Rust Off safety seminar put on by the Transport Canada safety officers for the local flying club and the general aviation population.. I spoke with one of the presenters and told him that we were starting to build a Bearhawk. Our club is the only one in the area and is has a water base where most fly floats and skis with a couple wheeled aircraft at the airport. To the point. The safety officer recommended that we bump the build registered total load at the outset from 2500 to 2700 to allow for floats. Certified aircraft in Canada can add 200lb.s to their total weight on floats w/o paperwork. Experimental aircraft are only allowed to fly their total weight floats or no floats. The TC safety officer said to register it at 2700 is easier. Where as registering at the build at 2500 then try to get the registered weight changed to 2700 to legally fly floats with max useful load is a painful process.

[JimParker256]

I believe it would be the same here in the US... Once the limitations are set, you can petition to change them, and the FSDO will likely accept the changes, but will almost certainly require a new "Phase 1 Test Flight" period to validate performance at the new numbers. So, if you plan to fly it at 2700 lbs on floats, I would certify it that way to begin with.

I will see our local DAR on Saturday, and will confirm this with him, but that's what I believe he told me last time we had this discussion.

[JimParker256]

Confirmed with our local DAR - once certified as EAB, changing the gross weight would require going back into Phase 1 test flight for at least 5 hours, and receive new operating limitations from the FAA.

[Zac Weidner]

So I can see that the useful load will fulfill my needs from what I've learned here.
Do you think it's likely to be able to get a 75% power 160 mph cruise speed at altitude (7-8,000ft)?

Also, I could call and get quotes, but what is insurance like on experimentals? The tailwheel and experimental makes me leery that insurance premiums will be sky high. Or is it like other things where experimental makes it more affordable?


Sent from my iPhone using Tapatalk

[whee]

There is a EAA webinar about EAB major changes and it talks about gross weight. Basically the builder can change the gross weight to whatever he wants whenever he wants but the plane must go back into Phase 1 for 5 hours...atleast that's what the webinar said.

My insurance quote came in exactly the same as the quote I got for a Maule. According to my broker experimental insurance is more expensive than for certified planes but in my case it wasn't. But Maules are known for being expensive to insure. When I got quotes I was airplane shopping so I had the broker quote $60k hull valve for a Maule ($2600), BH($2600), Cessna 180 ($1800) and a Cessna 182 ($800).

[Chris In Milwaukee]

Sidetracking, but what kind of Maule? And what is your TW experience? I was looking to partner with a local Maule owner on my field, but they wouldn't touch me for under $4500. Maybe they just didn't want to write it. I didn't check for a policy just for myself.

[whee]

M6-235 was the specific model but the broker said it didn't really matter what model Maule. At that time I had 300hrs with 296hr TW(Luscombe). Had it quoted as though I had 10hrs in each type as I figured I could get some time through friends.

Maybe worth noting, Avemco was the only outfit that would touch me when I had zero time and wanted to insure our Luscombe. Cost me $2500 for $25k hull that first year. Once I hit 100hrs it dropped to about $1200/yr.

[Chris In Milwaukee]

Thanks for that bit of info. Good data point. Now back to your regularly scheduled program :-)