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Hovey Delta Hawk Build

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Barnstormer

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Feb 10, 2017
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Hello All;

I would like to build a Hovey Delta Hawk biplane so not only am I looking for a set of plans but I also have a question regarding the structure that one of you knowledgeable stuctural engineer types might answer...or at least point me in the right direction of finding an answer.

I have seen and read several threads now regarding the use of "alternate materials" I.E rectangular tubing and gussets ala' the Aerotique Parasol or the extruded aluminum angle of the Beeson Chuckbird/Texas Parasol design.

Would either of these materials be feasible for use in the Delta Hawk fuselage structure vice round tubing? 6061 T6 extruded tubing is virtually unobtainable where I am but the rectangular and angle is plentiful and very reasonable cost-wise.

If using the rectangular or angle material, how would I determine an equivalent strength factor vis a vis the round tubing called for in the plans?

I am leaning somewhat to the angle at the moment due to the ability to use solid rivets vice pop rivets for strength but I do still have a large supply of aircraft grade pop rivets if it turns out that I need to use them on either the angle or the rectangular tubing.

I like the Delta Hawk design because of the easy entry/exit and because well, I just like open cockpits and biplanes. At 6'3 and at my age though, I no longer have the contortionistic ability to bend, fold and wriggle under a wing and between cabanes to get into the cockpit of a parasol.

Any ideas or advice? Leads on plans? Bob Hovey passed away several years ago and apparently the family no longer offers the plans.

Thanks for any ideas.
 
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Victor Bravo

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You're in the Pacific Northwest, and you cannot find 6061-T6 tube? After reading that post I expected to you to say you were in Kuala Lumpur. I'm sure that you have some metal supply company there that sells the AL angle or rectangle tube you mentioned is available.

Whoever the supplier is, they are already in the business of getting aluminum from the mills, shipped on large trucks, to that supplier. Even if you have to "special order" the tube from your supplier the shipping will be a lot less than using commercial freight.
 

Barnstormer

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Victor Bravo;

Yes, there is a metal supply place within reasonable distance but they will not order the tubing; I have already asked them.

There is another but it is some distance away. I am waiting on a call back from them now. In the meantime I wanted to see about these alternatives as I have read positive things about using these alternative materials in structures.

The aircraft supply houses want an arm and a leg as well as 3 fingers off of one hand for the round tubing. Since I am retired and not made of the gold stuff I would like to try to keep the cost as reasonable as possible commensurate with safety. I always try to keep in mind the immortal words of Josey Wales: "Dyin' ain't much of a livin'"
 

Victor Bravo

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OK, I understand your motivation for seeking an alternative to the tube. However, taking an existing design and changing the main structural material is not "inexpensive" either if you consider research and engineering time as having an equivalent dollar value.

As with so many of these discussions on HBA, everything depends on what you are trying to accomplish. For example:

Why have you chosen the Delta Hawk specifically? Was Bob Hovey your uncle or grandfather? Or are you looking for an inexpensive ultralight?

If you cannot use round tube because it is difficult to get, then why not build an airplane that was designed for a material you can get cheaply ?

Even the Texas Parasol used round tubes in the wings. Most all of the aluminum ultralights use tubes somewhere.

I have no knowledge of the Aerotique Parasol, so I don't know whether it uses round tubes in the wings. The consensus is that there are no Aerotique plans available anyway, so you will have more trouble finding the plans than getting any materials tube or otherwise.

So tell us what materials ARE available there. Can you get 6061-T6 sheet aluminum in thin gauges? Can you get good Marine or Aircraft Plywod? Can you hand pick Spruce or Douglas Fir someplace locally?

Graham Lee offered plans for something called the Beamcraft, that was designed around rectangular aluminum tube used in the window industry. The "APEV Pouchel" series of ultralight aircraft now uses square or rectangular tube.
 

TFF

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I would not substitute. Too much work to get it right. Price wise, airplane builders are notoriously cheap; if the parts cost a lot, they are the cheapest ones they could make work. There is always a more expensive way. That thing looks way harder to get into than a parasol. Bottom wing in the way.
 

Barnstormer

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A few developments since this afternoon. I received the call I was waiting for from the metal supply place and they said that they can order the tubing that I need so that renders the question of alternative materials moot.

But to answer your questions anyway, Victor Bravo; I like the Hovey because it does everything that I want it to do in the way that I want it to. I like the open cockpit, lines, the nostalgic look, the performance and economy of it as well as the fact that the wings are fairly easy to dismount for storage and transport. The only other aircraft that would appeal to me the same way for the same reasons (except for wing removal) is the SNS-8 Hiperlight. It is the only one of the airplanes that I have owned that I really regret selling.

Another design that I have owned before and would have no hesitation in owning again is a Mini-Max. They have proven to be very sturdy if built right, perform nicely and the wings remove fairly easily. Being made of wood though constant inspections are needed as well as care in maintenance to not nick or ding the wood sealant so moisture doesn't get in and begin delamination or other problems.

Here in the northwe(s)t the climate is such that even though marine grade wood is available and many boats are floating around made from it, wooden aircraft structures take a beating from the elements unless kept in a closed dry hangar; open faced hangars don't provide enough protection. I have nothing against wood though as I have owned and flown a Mini-Max before. I have also checked out Pietenpols and Flybabys for light sport flying but I don't fit into Piets and a Flybaby is just not what I am looking for at the moment. But I won't rule one out in the future. Also, round tubes would still have been used in the wings; I was asking about the fuselage only but again, moot since I have a source for the tubing now. Although I have seen things like that done before hence my curiosity and asking the feasibility question; as well as seeing other threads of a similar vein elsewhere in the forums here. I am well aware of the potential for re engineering. There is always a cascade effect when you change one aspect, others have to be change to accommodate. This is why I was asking for input, especially from engineer types with a background in stress analysis and things. But ALL input is appreciated.

With regards to other materials for construction; fiberglass is of course an option but it must be thick and thus heavy to provide structural strength.

Clad aluminum sheet in thin gauges is an option. I do have extensive experience in that medium and there is a supplement to the Delta Hawk plans to cover the fuselage in sheet aluminum vice fabric to make a "Super Delta Hawk". But I will stick with the fabric covering.

TFF;
The Hovey is actually very easy to get into and out of. The cockpit coaming between the engine and the forward cabanes hinges up to the side giving you a large area to climb up and step into (there is a step forward of the wing leading edge), turn around and settle yourself into the seat then bring the coaming back down and latch it in place. The Hiperlight has a similar entry/exit procedure but you are hinging the canopy instead of the coaming. Mini-Max's are the same if they have the canopy but I am too tall for an enclosed Mini-Max/Z-max, etc. so I flew mine with the open cockpit and just used the step to step up over the leading edge into the cockpit, turn around, and sit down. I don't have to bend, fold or get mutilated trying to slide in.

I would still like to hear from engineer types about the feasibility of using rectangular or square tubing and how much engineering re-computation would be necessary; just for curiosity.

Also, would love to hear from anyone with leads on plans, projects or flying Delta Hawks for sale anywhere near Seattle.
 
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pufferfish

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Have you had any luck in locating plans? Have you started the project? This Delta Bird is near the top of my list as a first build for the same reasons you like it. It's fairly easy to build, it will fly on low horsepower, and looks like an airplane.
 

plncraze

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Mr. Hovey's son had posted on the Yahoo group for Hovey's planes. You could try there.
 

wsimpso1

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A few developments since this afternoon. I received the call I was waiting for from the metal supply place and they said that they can order the tubing that I need so that renders the question of alternative materials moot.
Good! Unless you are already a good structures guy, I would never have you start substituting structural shapes for other structural shapes. My perspective as a guy who can do all the engineering is this:
  • Figure out which materials you like working in and narrow your choices to that material set;
  • Buy plans for an airplane using that material set that has a good history and then stick to the plans;
  • If the airplane you like has a known issue and a known good fix that has a good history, then stick to the plans plus the known good fix.
Now that I have said that let's get into why I do not think you should be doing any substituting. Using the example of a fuselage truss, each element of the truss has most likely already been checked out for adequate strength. Usual failure is buckling, which can come in two forms - column buckling and crippling. There are other modes, plus the various reinforcements and attaching methods. There is a bunch of work in it, and while someone already practiced in the art might be able to go through it pretty easily, a newbie is likely to make some mistakes... Then once you are in the aeroloads and truss calcs, for another set of structural shapes, you might be able to optimize the truss with the new shapes for the elements and get back some of that weight, but that too has tails and opportunities for mistakes...

Then there is weight. WEIGHT IS THE ENEMY. In column buckling and crippling, the round tube is just about the lightest way to get to strength. A square tube of the same size and wall as the round tube will be 4/Pi times as much weight while being somewhat lower strength in crippling than that round tube... Angles will be less likely to cripple but will have to be quite a bit heavier to get the same Euler/Johnson column failure strength. Then there is attachcing all this stuff together. To do all of this stuff would require you to become good at truss calcs as well at column buckling and crippling.

Learning how to do this engineering and check your work and get to a good result might be fun, but is your goal to build an airplane or to become an airplane designer and structural engineer? And how long would you accept for learning the engineering? So, I say pick an airplane with a good history, stick to the plans except where there are known good fixes for known issues, build and fly. Trust us when we say it - Building and flying an airplane is quite an accomplishment all by itself.

Billski

Besides designing the truss elements, you would also have to
 

Dana

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Looks like it's been over two years since the OP has been seen here. I wonder if he ever built it?
 

Barnstormer

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Feb 10, 2017
Messages
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Pacific NorthWET
While I was finally able to get a materials source I was unable to get a set of plans. I tried the Yahoo group with no luck. A local acquaintance supposedly had a set of plans but they turned out to be for a different aircraft.

I have since been rebuilding/restoring a 1984 vintage Cloud Dancer Jenny 5/8 scale Jenny ultralight that is ready for cover. I do need to find a different redrive for it to replace the OEM Winters planetary gear drive that had such a bad rep for seizing up or throwing props in flight. But that can wait for awhile.

I have also been caught up in this thing called "life"; stripping out a house, remodeling, painting,etc. then gtting it on the market, selling it and moving to another state. It puts things on hold for awhile but the weather is turning nice and I have some time now so I will be getting back to it soon.

P.S. Haven't posted in awhile because I haven't had time nor anything constructive to pass on.
 

Doran Jaffas

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Jun 25, 2019
Messages
249
Hello All;

I would like to build a Hovey Delta Hawk biplane so not only am I looking for a set of plans but I also have a question regarding the structure that one of you knowledgeable stuctural engineer types might answer...or at least point me in the right direction of finding an answer.

I have seen and read several threads now regarding the use of "alternate materials" I.E rectangular tubing and gussets ala' the Aerotique Parasol or the extruded aluminum angle of the Beeson Chuckbird/Texas Parasol design.

Would either of these materials be feasible for use in the Delta Hawk fuselage structure vice round tubing? 6061 T6 extruded tubing is virtually unobtainable where I am but the rectangular and angle is plentiful and very reasonable cost-wise.

If using the rectangular or angle material, how would I determine an equivalent strength factor vis a vis the round tubing called for in the plans?

I am leaning somewhat to the angle at the moment due to the ability to use solid rivets vice pop rivets for strength but I do still have a large supply of aircraft grade pop rivets if it turns out that I need to use them on either the angle or the rectangular tubing.

I like the Delta Hawk design because of the easy entry/exit and because well, I just like open cockpits and biplanes. At 6'3 and at my age though, I no longer have the contortionistic ability to bend, fold and wriggle under a wing and between cabanes to get into the cockpit of a parasol.

Any ideas or advice? Leads on plans? Bob Hovey passed away several years ago and apparently the family no longer offers the plans.

Thanks for any ideas.
If you get a lead on those plans please let me know as well. 100 years ago or so I used to have a Hovey Wing Ding two. I had the honor of meeting Bob Hovey back in the late 70s when I had this aircraft. I met him at Oshkosh when I brought it in on a trailer. I have not flown it and truthfully I never did fly it but it was a memory I hope I will have until I'm at least a hundred and four. The Delta hawk even for today is a very nice ultralight so if you happen to come across a set of plans again I would be very interested myself. My current aircraft and one that I will probably keep again until I'm a hundred and four is a Tailwind W8 but the Hovey designs have always held a spot in my heart.
 

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plncraze

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Many years ago Mr. Hovey's son was on the Yahoo group forum and said his father was the only person who could legally sell plans. A few folks asked to get these and he never replied. I don't see anyone else selling the later plans either.
 

vhhjr

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You might want to contact Brian Carpenter at Rainbow Aviation in Corning, California about the Hovey Delta Hawk. I recall his telling of building one and finding the flight characteristics to be very strange.

Vince Homer
 

PagoBay

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Maybe not so relevant to the specific point, but for the benefit of later readers, Brian and Carol Carpenter, founders and owners of Rainbow Aviation, and their popular LSRM course are now based out of Missouri.
 
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Mavigogun

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You might want to contact Brian Carpenter at Rainbow Aviation in Corning, California about the Hovey Delta Hawk.
I drove by Rainbow in early January- place looked gutted. Series of unfortunate events, as I understand. Not topically useful, just triggered memory.
 

PagoBay

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Not sure why Rainbow Aviation has not updated their website to give new address information and telephone contacts. Trust they are just busy.
 
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