Quantcast

My Design

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

TarDevil

Well-Known Member
Joined
Jun 29, 2010
Messages
657
Location
Coastal North Carolina/USA
It took a lot of courage to post here. I've been lurking for a long time and to say I'm impressed with the knowledge on this board would understate my feelings significantly. I'll state upfront that I know nothing. I've got some ratings, I flew myself for business for a while (wanted badly to fly professionally, but wasn't man enough to stand up to my dad... but that's another story), so I settled for trying to find my place in the corporate world with an eye turned towards the sky, wishing I were there.

I've drawn a plane I'd like to show you. I initially drew it back in 1986, but was influenced by another design to redraw it in 1996. The premise is an owner flown plane with international capabilities. The engines are diesel, and the ones that make most sense to me (on paper, at least) are Delthawk 180 HP. I don't see them getting a lot of love here, so I'd be interested in feedback. I know Deltahawk hasn't done much but put out paper for a long time, but I was encouraged to see them actually fly a plane to Oshkosh this year... maybe they'll actually produce something!

Unless I win the lottery I'll never build this airplane, but I've enjoyed playing with the design over the years and I'd like to have some input to play with in my head, if you guys have the time and inclination. Also, if one of you has some 3D software and could create some nice images of this plane, I'd feel almost like I had flown it. :)

Again... with no engineering background all my numbers are WAGs, but my estimates are:

Gross wt - Approx 7,000
Fuel - 350 Gals
Cruise - 170 kts
Range 4500 Nautical Miles
Wing Area - Est. 185

 

spduffee

Well-Known Member
Joined
Sep 22, 2011
Messages
567
Location
Renton, WA
Thanks for posting this. I think it has a lot of potential. I am not an Aero-engineer either, but I think Diesels for long range flight make a lot of sense for more than one reason. I don't think I have seen a tri-motor in a modern airplane before, but I can see the safety aspect of that, and it's a good idea. How many passengers would this hold? Do you have any other drawings - elevations...?
I think a lot of us would love to fly corporate, but have been discouraged to do so by others. My goal is to become a licensed CFI - at least I can help train potential career-guys.
I look forward to learning more about the design. Good job!

Shawn
 

bmcj

Well-Known Member
HBA Supporter
Joined
Apr 10, 2007
Messages
13,495
Location
Fresno, California
Welcome to HBA TarDevil.

Appearance-wise, your design is a winner. Functionally, I'd consider a couple of changes...

First, it might be hard to balance this design with your three heaviest loads (the engines) all hanging out in front of the wing. With the long boattail on the fuselage, you might consider moving the center engine to the back end as a pusher.

Secondly, take advantage of the 3-engine layout and plan on a big engine/little engie combination. Size the little engine(s) for cruise and size the big engine for the power you will need for a 3 engine take-off and climb. You have your choice on which engine(s) to use for cruise and which one(s) aid the take-off. If you have the single center engine as your big climb engine, then losing either of the outboard engines will not be so detrimental, and I think that you might get a bigger drag reduction by feathering the rear engine in cruise because it hides behind the fuselage. On the other hand, cruising on the outboard engines might mean less noise in the cabin and better cruise efficiency (puller vs pusher props), but it means that engine loss in cruise would require quicker action by the pilot.
 
Last edited:

spduffee

Well-Known Member
Joined
Sep 22, 2011
Messages
567
Location
Renton, WA
you might consider moving the center engine to the back end as a pusser.
Good idea bmcj about the third motor being a pusher (I don't think you want a pusser, on climbout, especially...hehe). That makes a lot more sense and balances it all out nicely.
 

TarDevil

Well-Known Member
Joined
Jun 29, 2010
Messages
657
Location
Coastal North Carolina/USA
Thanks, bmcj. I had considered a pusher engine, but in my uneducated mind I thought it might actually be harder to balance. I just assumed the cabin, fuel, etc could be designed around the CG with to balance the engine weight. I wouldn't be opposed to a pusher concept.

RE the big engine/small engine... I considered that as well and ruled it out for safety reasons. Depending on where you are in your flight, the loss of one of your small engines means you are committed to use of the large engine and higher fuel consumption, which may compromise destination. If over water, you may be in trouble. Not so much of a problem if light enough that you can shut down the other small engine and use the center engine alone. Just depends on your weight and power requirements.

Again, I've a lot to learn and would welcome input.

Thank you for the welcome!
 

TarDevil

Well-Known Member
Joined
Jun 29, 2010
Messages
657
Location
Coastal North Carolina/USA
Re: My Design-Pusher, I like it

This is the best I could do with my limited computer skills and software...


I do hate saying goodbye to the airplane I've been looking at for the last 15 years!

Here's what's bothering me...this has complicated entry/loading for passengers. In my previous design, I envisioned passengers passing under the raised tail and loading through a clam/airstair door in the aft cabin. Now, there's not an easy place for entry.
 

bmcj

Well-Known Member
HBA Supporter
Joined
Apr 10, 2007
Messages
13,495
Location
Fresno, California
Re: My Design-Pusher, I like it

Here's what's bothering me...this has complicated entry/loading for passengers. In my previous design, I envisioned passengers passing under the raised tail and loading through a clam/airstair door in the aft cabin. Now, there's not an easy place for entry.
Well, you do raise a very good point here and one that I had not considered in my earlier suggestion. I think the boom would still be too low to comfortably walk under, but from the very rear under a high tail would certainly work on your original concept).

If you were to go with your original concept, you would have to have a pretty light engine in the nose.
 

Vision_2012

Well-Known Member
Joined
Apr 21, 2010
Messages
274
Location
Shady Cove, OR
Latest on Deltahawk was noted in the EAA Experimenter. - Their production of the 180HP is about to receive certification.
I like the way their PR has been handled, no hype just facts. Other a/c businesses should follow their lead.
 

TarDevil

Well-Known Member
Joined
Jun 29, 2010
Messages
657
Location
Coastal North Carolina/USA
Does it really need the center engine? It's still pretty cool without it.

View attachment 35670
I personally wouldn't wanna cross an ocean without it... not routinely. Nor would I want to risk an engine out in a typical twin layout with that much weight. Three engines allows optimized power for the airframe without as much % power loss should you lose an engine.
 
Last edited:

TarDevil

Well-Known Member
Joined
Jun 29, 2010
Messages
657
Location
Coastal North Carolina/USA
Latest on Deltahawk was noted in the EAA Experimenter. - Their production of the 180HP is about to receive certification.
I like the way their PR has been handled, no hype just facts. Other a/c businesses should follow their lead.
I hope so. I've been following their website for years, and they've said that every year. I'd love to see them make a go... I personally think that engine has a lot of promise.
 

TarDevil

Well-Known Member
Joined
Jun 29, 2010
Messages
657
Location
Coastal North Carolina/USA
Maybe a push/pull with the big engine in back and smaller in the front?
Problem would be if the big engine quit on take off or early in the flight, the small engine couldn't handle the load. I envision this as an aircraft that the owner/pilot could use routinely for ultra long-distance travel. A tri-motor would be expensive; but far less expensive than any other international capable aircraft without a type rating, and the safest option I can think of.
 

TarDevil

Well-Known Member
Joined
Jun 29, 2010
Messages
657
Location
Coastal North Carolina/USA
Re: My Design-Pusher, I like it

If you were to go with your original concept, you would have to have a pretty light engine in the nose.
I've thought about this more, and I can't see the difference between my tractor concept and a big single. There have been successful tri-motors in the past. What am I overlooking?
 

fly2kads

Well-Known Member
HBA Supporter
Joined
Jan 2, 2010
Messages
1,680
Location
Justin, TX
TarDevil, nice looking concept. I agree with bmcj that it would likely be tough to balance that configuration. I wonder if lengthening the tail booms would help enough with that? Have you set up a W&B spreadsheet for it? Your data trumps our eyeball engineering!

I like the twin layout. That looks very achievable. I don't have any over-water experience, nor do I want any, so my opinions about the lack of the third engine should be taken for what you paid for it.

BTW, thanks for throwing this out here for us to view and comment. This is fun!
 

TarDevil

Well-Known Member
Joined
Jun 29, 2010
Messages
657
Location
Coastal North Carolina/USA
TarDevil, nice looking concept. I agree with bmcj that it would likely be tough to balance that configuration. I wonder if lengthening the tail booms would help enough with that? Have you set up a W&B spreadsheet for it? Your data trumps our eyeball engineering!

I like the twin layout. That looks very achievable. I don't have any over-water experience, nor do I want any, so my opinions about the lack of the third engine should be taken for what you paid for it.

BTW, thanks for throwing this out here for us to view and comment. This is fun!
I don't have ANY real data... eveything of mine is just eyeball!!

Yeah, some time ago I realized that the booms could be lengthened... and there's room to pull the center engine in closer. In fact, once the booms are lengthened, the entire center section probably should be moved aft a bit.

This will never become reality unless I strike gold, but if I did win the lottery or my rich uncle left me some of his money, I wouldn't consider building the plane with less than three engines or without diesels. That's just MY preferences. I'll just stay home otherwise.

And yeah, it's fun. That's about all I can do with it!
 

Topaz

Super Moderator
Staff member
Log Member
Joined
Jul 29, 2005
Messages
14,112
Location
Orange County, California
...First, it might be hard to balance this design with your three heaviest loads (the engines) all hanging out in front of the wing....
Nothing moving the wing forward a little, and/or adding a little forward sweep wouldn't fix. This is actually one of the more reasonable design sketches we've seen here lately, especially in that it actually seems suited to the intended purpose. Lots of room near the CG for fuel in those booms, a reasonable aspect ratio for long cruising flight and, yes, an opportunity with all those engines to thrust match for a long cruise mission.

Welcome to the forums, TarDevil. I think you've got a good beginning! :)
 

TarDevil

Well-Known Member
Joined
Jun 29, 2010
Messages
657
Location
Coastal North Carolina/USA
Re: My Design-Pusher, I like it

Certainly not the same, but your concept reminded me of the Adams 500.

Adam A500 - Wikipedia, the free encyclopedia
Most people who see my plane think it's origins are from the Adams, and I can certainly see why. But you may be surprised to realize where the inspiration came from. A hint comes from post #19!

And thank you, Topaz.
 
Top