Notices
Q-500 Racing Discuss AMA 428, AMA 424, and any other variants of Quickie 500 racing

Optimal Fuselage Design

Old 11-05-2004, 10:45 AM
  #1  
oddy
Thread Starter
 
Join Date: May 2003
Location: Mexico city, MEXICO
Posts: 353
Likes: 0
Received 0 Likes on 0 Posts
Default Optimal Fuselage Design

Hi everyone:

Im on my building time to begin next year races fully prepared with at least 3 Q500.

My question is the following, some Q500 fuselages such as the V-max or the Bird of Pray have a design in which the F2 is wider than the F3.

Anyhow I´ve seen some other designs in which F3 is Wider than F2 (I think Vortex is like this)

Could anyone comment the reasons and advantages of this 2 differente fuse designs.

(F2 Former at the leading edge)
(F3 Former at the Trailing edge)


Best Regards.
V*ctor
Old 11-05-2004, 01:29 PM
  #2  
HighPlains
My Feedback: (1)
 
Join Date: Mar 2003
Location: Over da rainbow, KS
Posts: 5,087
Received 4 Likes on 4 Posts
Default RE: Optimal Fuselage Design

Many designers like to meet the height and width of the fuselage requirements at the same location. Classic design, and completely wrong when you don’t have fillets to avoid separation of the air at the fuselage/wing junction. For the longest time, it was thought that you could not have laminar flow of the air down the length of the fuselage when you have a prop on the nose. Well this has been disproved since aircraft like the Nemesis were so thoroughly analyzed. It was found that the propeller wake would travel down the fuselage as a turbulent pulse of pressure, then the local flow would quickly revert to a laminar stream. The nose of our aircraft is a bit on the dirty side, but by expanding the width of the fuselage as we reach the trailing edge of the wing, we can help the local flow – perhaps by making the flow laminar, or by preventing separation at the wing/fuselage junction. Regardless, it works quite well, though is only used by a few designers. (Guys that I used to beat on a regular basis, or the guys that they now beat. Well, it took several years before the high aspect ratio wings caught on too.) So to clearly say it, place the maximum width of the fuselage at the trailing edge of the wing. How you go from the nose to this point is up to you, though I kind of like to come back nearly straight from the firewall to the thick part of the wing before expanding. I have also tried a straight line from the firewall to the trailing edge, so it is still open to play with.
Old 11-05-2004, 07:55 PM
  #3  
Ed Smith
Senior Member
 
Join Date: Dec 2001
Location: Brantford, ON, CANADA
Posts: 3,305
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Optimal Fuselage Design

Victor,

here is a picture of my Quicky fuselage. I mold my own. The shape illustrates the description in High Plains post of the wide point at the wing trailing edge.

Ed S
Attached Thumbnails Click image for larger version

Name:	Qo41417.jpg
Views:	56
Size:	48.4 KB
ID:	190276  
Old 11-05-2004, 10:10 PM
  #4  
HighPlains
My Feedback: (1)
 
Join Date: Mar 2003
Location: Over da rainbow, KS
Posts: 5,087
Received 4 Likes on 4 Posts
Default RE: Optimal Fuselage Design

Great picture Ed.

Note the shape of the fusekage behind the wing.

Now how do you close out the fuselage platform behind the wing? It seems that a lot of the high performance home built aircraft designers agree. Pinch the fuselage tail-cone to minimize surface area. But I like numbers, especially if they are attached to NASA or NACA (predated NASA). So I use the platform of the NACA duct to complete the tail, by stretching it in length slightly. It is thought that since the air becomes turbulent behind the wing, that this shape will recover some of the energy and add a bit of thrust. At any rate, it does reduce the area greatly, for lower drag and lower weight of the aircraft.

bob
Old 11-06-2004, 10:03 AM
  #5  
bl10
Senior Member
 
Join Date: Dec 2001
Location: Chatsworth, CA,
Posts: 303
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Optimal Fuselage Design

Bob:
I’ve always heard the object of having the wide point of the fuse at the trailing edge is to make the fuse cross section area as constant as possible including the wing. Is this not where the “coke bottle” fuse on some 2nd generation full scale jets came from? Your explanation, however, sure sounds better. Now if I could only understand it.

Barry
Old 11-06-2004, 12:42 PM
  #6  
HighPlains
My Feedback: (1)
 
Join Date: Mar 2003
Location: Over da rainbow, KS
Posts: 5,087
Received 4 Likes on 4 Posts
Default RE: Optimal Fuselage Design

Barry,

The “coke-bottle” fuselage shape was originally applied to the “Century Series” of fighters of the late ‘50’s when they found the first one couldn’t go thorough the speed of sound due to transonic compression drag. So they applied a modification of a 1930’s theory by a NACA engineer named Dr. Richard Whitcomb that became known as the “area rule” to the F-102. He had an amazing career spanning most of modern flight, including the development of winglets.

I arrived at the expanding fuselage through a different path. A very long time ago, I was reading a general aviation magazine a short article about a guy who had a Piper Cub airplane that wanted a third seat. So he just cut the fuselage down the center and stretched it wider to make the rear seating area wider. So he ended up with a three seater with the pilot in front, and a double seat in the back. What caught my eye was a single sentence where he claimed the airplane was 5 mph faster after the change. The way it was written, you could tell the writer didn’t d believe it. So I had just got back into Quickie racing with the then new Nelson engine and decided to try it.

I was just developing a design call “Thumper” where I first used it. I wasn’t yet into short fuselages or the pinched “NACA Duct” tail, and the tank was still in front of the wing. But the results were stunning, as if I was flying a clean airplane and everyone else were pulling drag chutes. At that time Dodgers and Revlutions were the hot designs. I took the Thumper to Medford in 1994 and won every heat, and lapped most of the airplanes there. It was radar’ed on the course at 172 mph, while most of the rest were in the high 150’s and mid 160’s.

Bob
Old 11-06-2004, 04:17 PM
  #7  
PylonWorld
Banned
 
Join Date: Dec 2001
Location: Monroe, NC
Posts: 1,332
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Optimal Fuselage Design

Barry,

The fuselage design with the wide point at or near the wing trailing edge has been around for a long time. Even the Piper Cherokee series used it. The important part is not an expanding cross-section. The important part is stabilizing flow at the fuselage and wing junction. It is very hard to design fillets that adequately do the job. And of course Quickies don't have fillets at all. Neither do the Piper PA-28 (the Cherokee line including the [link=http://www.newpiper.com/fleet/arrow/index.asp?Model=Arrow]Arrow[/link], etc), the Mooney M20, the [link=http://www.raytheonaircraft.com/beechcraft/bonanza/bonanza_a36.shtml]Beechcraft Bonanza[/link] and most other low wing full scale aircraft.

Numerous (fullscale) Formula 1 aircraft (like the Mace Shark) have used the principal all the way back to the 40's. Many used a hybrid approach to keep the wetted area down also. The problem with the widest point at the rear of the wing is that the wetted area can become large enough to offset part of the drag reduction. That is why the coke bottle shape is important. On a Quickie, you don't want the high point at the rear of the fuselage along with the wide point because the cross-section will be larger than it needs to be.

The fullscale Lancair planes used the expanding width into a Coke bottle shape in the 80's. Check out the [link=http://www.lancair-kits.com/]Lancair Performance Kit Aircraft[/link] page for some fullscale applications of the principal. Lancair is pronounced Lance-Air.

A lot of research was published in the 60's and 70's on the wing/fuselage intersection. Many of the modern business jets use a junction that looks totally wrong from an intuition standpoint. Take a look at the [link=http://www.raytheonaircraft.com/beechcraft/premier/premier.shtml]Beechcraft Premier 1[/link]. The wing / fuselage intersection can cause as much as 1/4 of the total drag of the airframe. On the jets, the increased cross-section is a small price to pay for the drag reduction.
Old 11-06-2004, 07:41 PM
  #8  
HighPlains
My Feedback: (1)
 
Join Date: Mar 2003
Location: Over da rainbow, KS
Posts: 5,087
Received 4 Likes on 4 Posts
Default RE: Optimal Fuselage Design

Frank,

I don’t recall seeing any GA factory tin airplane with an expanding the width fuselage. Every GA airplane that I have ever sat in was narrower in the rear seat than the front seat Of the three mentioned, the Cherokee is by far the slowest. I flew one from the right seat some and can only describe it as being similar to driving a station wagon with four flat snow tires on a muddy road.

Looking at a three view of the Shark designed by Harvery Mace (first flown in 1970), I see the widest point of the fuselage at about the 1/3rd point of the wing. It had wing fillets and a very low aspect wing. It only qualified at 198 mph. He sold it and bought a BOAT, so I guess it’s speed was not so great.

The Nemesis does have the expanding width fuselage. I assume that this was intentional, though when I met Jon Sharp, I was surprised at how big a man he was (around 6’ 2” or 3”, 200+ lbs.). So his airplane cockpit was much larger than most Formula One designs, where they shoehorn a smaller pilot into them.

Lancair uses fillets, but they do pinch the fuselage behind the wing to reduce surface area. But they also start to contract the fuselage width before the trailing edge of the wing.

On Quickies, most meet the height requirement of the rules where the wing is thickest, not at the trailing edge. Meeting the quickie width requirement at the trailing edge to lower drag was not widely known in RC pylon racing circles before I published it in Model Aviation in ’98. You can look it up in AMA’s digital archive. No kits or designers used it prior to that publication, and only a racers in Northern California through Washington had seen it. It always surprised me how slow people were to adapt the concept. I think Chuck Bridge was the first with the Vortex, but I left the area and pylon racing for about three years during the ascension of Randy, though I did call him a win in the ’98 or ’99 championship race

I have since found a really good collection of works on drag reduction written by Bruce Carmichael. It is called “Personal Aircraft Drag Reduction”, self published in 1995. It is 200 pages of charts, graphs, sketches, articles, and references that compose his entire life’s work. Unlike most tomes on the subject, he dives into fuselage design as well as the wing that everyone else seems to stop at. In his final comment on intersection drag he agrees with what I had already found. But his best advice was “Don’t do nothing dumb”.

Bob
Old 11-06-2004, 09:10 PM
  #9  
garys
Senior Member
 
Join Date: Jan 2002
Location: Stansbury Park, UT
Posts: 937
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Optimal Fuselage Design

Bob, whose "Frank" that you were directing your comments to? I believe his name is actually "Don"....

While the expanding width fuse is the "in thing" with fuses right now, I wonder if it really is making that much of a difference, since we have that big hunk of draggy aluminum hanging on to the front of a 2.25" square firewall. No wood airplane has ever turned the times of my QuikV5 from back in 1999, and while the fuse did coke bottle towards the rear, the widest point was at about the 1/3 point of the wing. Very few people have gone as fast with composite airplanes to this day. I don't believe anybody's actually done any real measured analysis directly comparing the two different fuse types, with absolutly no other factors that could make a difference.

GS
Old 11-06-2004, 09:57 PM
  #10  
HighPlains
My Feedback: (1)
 
Join Date: Mar 2003
Location: Over da rainbow, KS
Posts: 5,087
Received 4 Likes on 4 Posts
Default RE: Optimal Fuselage Design

I was refering to a cultural icon.

http://www-tech.mit.edu/V110/N57/sinatr.57a.html
Old 11-06-2004, 11:24 PM
  #11  
PylonWorld
Banned
 
Join Date: Dec 2001
Location: Monroe, NC
Posts: 1,332
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Optimal Fuselage Design

Bob,

The world of aviation owes you a debt of gratitude for your amazing discovery.

The Lancair 360 is wider at the trailing edge than at any point forward. It was the precursor to the Lancair IV and dates to the 80's. The Glassair low wing planes also used your amazing concept. I worked on both a Lancair 360 and Glassair III. I later got to fly in them.

As to Cherokees and other low wing spam cans being wider in the front seat, it is predominately because the back of the rear seats is behind the trailing edge. Ever actually look out of the second row and see the trailing edge? Doh!

I've flown a lot of hours in a lot of different airplanes, left seat and right seat, and the Cherokee series fly just fine. Yes, the PA-28's and PA-32's with the semi-tapered wings fly better. But any capable pilot adjusts to the airplane. My favorite transit airplane to fly is the Mooney M20C and my second favorite is the V-35 Bonanza.

I looked through some F1 3-views and from what I see, a number of plane designers owe you big time for your discovery.

I have one simple question. Which has more drag at a slight AoA, a straight flat surface, or a curved surface? Please enlighten me.
Old 11-06-2004, 11:54 PM
  #12  
HighPlains
My Feedback: (1)
 
Join Date: Mar 2003
Location: Over da rainbow, KS
Posts: 5,087
Received 4 Likes on 4 Posts
Default RE: Optimal Fuselage Design

Chairman of the bored,

Frank - I stand by my statements.

Your commits on the Mace Shark were rather strange
Numerous (fullscale) Formula 1 aircraft (like the Mace Shark) have used the principal all the way back to the 40's.
since the three views plainly show different.

So I have to wonder -
Still sucking the juice out of your LiPo batteries?
Old 11-07-2004, 12:14 AM
  #13  
PylonWorld
Banned
 
Join Date: Dec 2001
Location: Monroe, NC
Posts: 1,332
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Optimal Fuselage Design

Dribble,

The Mace Shark was mentioned because it was one of the first racers I knew of to have the distinctive fuselage shape aft the wing. Sorry I used it in a compound sentence.

Since you are bored, try this Yahoo! search [link=http://search.yahoo.com/search?p=nemesis+pylon+racer&sm=Yahoo%21+Search&fr=FP-tab-web-t&toggle=1]nemesis pylon racer[/link] ... Yahoo! links are rated partially based on hits and partially on links to the page. The #1 link is interesting.

Nemesis debuted in 1991. This photo somewhat reveals the team's apparent use of your concept.

I'll have you know I prefer SoBe Adrenaline Rush energy drinks. They're much more refreshing.
Attached Thumbnails Click image for larger version

Name:	Db84641.jpg
Views:	55
Size:	58.7 KB
ID:	190598  
Old 11-07-2004, 08:26 PM
  #14  
Ed Smith
Senior Member
 
Join Date: Dec 2001
Location: Brantford, ON, CANADA
Posts: 3,305
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Optimal Fuselage Design

To both "Frank" and"Dribble"

Well do not stop now. The sparkling wit, the sarcastic humour, the display of knowledge, and/or lack thereof I find quite entertaining. Do continue for the amusement of us all.

Ed S
Old 11-08-2004, 12:02 AM
  #15  
Bill Vargas
Senior Member
My Feedback: (5)
 
Join Date: Jan 2002
Location: Apple Valley, CA
Posts: 1,987
Likes: 0
Received 1 Like on 1 Post
Default RE: Optimal Fuselage Design

ORIGINAL: Ed Smith

To both "Frank" and"Dribble"

Well do not stop now. The sparkling wit, the sarcastic humour, the display of knowledge, and/or lack thereof I find quite entertaining. Do continue for the amusement of us all.

Ed S
I'll drink to that,,, please pass me another "coldie"


BV
Old 11-08-2004, 07:19 PM
  #16  
PylonWorld
Banned
 
Join Date: Dec 2001
Location: Monroe, NC
Posts: 1,332
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Optimal Fuselage Design

Gary,

I'm with you on not being sure that there is a true advantage for the wasp waisted or "expanding width" fuselages. The Bird of Prey seems to be holding its own among current designs.

Even though I borrowed the shape that I used on the Smasher fuselage primarily from the Lancairs and Cirrus SR-20/22, I did some little things that I hope make it at least competitive.


Ed and Bill,

I'd be delighted.

Almost everything I've seen in R/C modeling related to aerodynamics, I've previously seen in full scale aircraft. These profile and flat foamie 3D planes are the only exceptions I can think of.

I learned to fly in a fleet of 3 Cherokee 140's. All were 150 hp planes made in the same year. Even so, they all were a little different and had their own personalities. One had a "climb prop" and was the preferred plane on hot high density altitude days, even though it was the rattiest of the three. None of the Cherokees are optimized for speed as they all have protruding head rivets. But the design has proven itself.

Here are a couple of quotes from the June 2004 Plane & Pilot magazine in an article entitled "An Enthushiast Cherokee" by Bill Cox the Senior Editor.

After all, the airplane made its reputation based on a docile stall and some of general aviation's most benign flying qualities. The littlest Cherokees have always been regarded as among the gentlest of trainers, so universally respected for their predictable manners that some instructors actually criticize them for being too easy to fly.
Stalls in a Cherokee 140 almost aren't stalls. Pull the power off, ease the nose 15 degrees above the horizon, and the airplane's eventual reaction will be a little more than a gentle nose-bobbing up and down as the wing alternately stalls and unstalls. If the airplane is properly rigged and symmetrically loaded, you can sit there with the yoke against the back stop, mushing slowly downhill with good rudder control and even a semblance of aileron response until you run out of altitude.

Landings deserve credit for making the Cherokee legendary. Like the airplane itself, they're sheer simplicity. A full flap stall is well below 50 knots, so a 65 knot approach speed works well. The wing is so predictable and the gear so forgiving that the Cherokee may be the easiest landing airplane in general aviation.
Does that sound like a poorly designed or poorly flying airplane? Interestingly enough, the Cherokees use a laminar flow airfoil with the maximum thickness somewhere between 40-50% of the chord. They are not speed demons, but that is not because of poor design. They are utility aircraft and have exposed rivet heads on the wing and the fuselage. The airplane in the article referenced picked up 12 knots with an improved exhaust system, and some speed mods from Laminar Flow of Daytona Beach to clean up draggy areas around protrusions.

Frank
Old 11-08-2004, 10:17 PM
  #17  
HighPlains
My Feedback: (1)
 
Join Date: Mar 2003
Location: Over da rainbow, KS
Posts: 5,087
Received 4 Likes on 4 Posts
Default RE: Optimal Fuselage Design

OK,

Here are links to a few drawings of the full size airplanes mentioned in previous posts as supposedly having an expanding width fuselages. By an “expanding width” fuselage, I am referring to a fuselage that increases in width from the leading edge to the trailing edge of the wing. Click on any, or all. Some like the Cherokee are constant width from the leading edge to the trailing edge. Others, like the Lancair IVP, start contracting before the trailing edge. I didn’t find a good 3-view of a Lancair 200, 320, or 360, but I recall them as being smaller versions of Lancair’s flagship airplane.


1966 Piper Cherokee 160 hp

http://www.aircraftpaintschemes.com/...AircraftID=122


Mooney 20JMSE

http://www.aircraftpaintschemes.com/...AircraftID=176


Beechcraft Bonanza V35B

http://www.aircraftpaintschemes.com/...AircraftID=198


Lancair IVP

http://www.aircraftpaintschemes.com/...AircraftID=352


Stoddard-Hamilton Glasair III

http://www.aircraftpaintschemes.com/...AircraftID=191



Area Rule fuselage – An interesting pair of pictures of the original F102 and the improved F102A. However it would appear that the librarian that composed this web page didn’t really know what they were putting together, since the photos are switched. I’m sure that NASA knew the difference.

http://www.1903to2003.gov/essay/Dict...le/DI103G1.htm


And finally the spam can designs did not typically pinch the fuselage behind the wing since they are built primarily from planar sheets of aluminum. As such, compound curves are expensive since it would require a much greater skill level and/or cost. So most of the fuselages have more or less a straight line from the wing to the tail. Perhaps that’s why they were so often referred to as a “tailcone”.

But composites have allowed aircraft like the Lancair’s to really reduce the surface area behind the wing. Since this is typically in turbulent air, it is an effective method of drag reduction.

And Gary, 1:05’s and 1:06’s are incredible, but I think with a expanding width fuselage you could go better. I want your airfoil, your engine, your thumbs, and your caller.

As far as the contour of the planform, Ed’s photo shows the basic concept. There are several variations of the concept to experiment with to find the optimum design, but my testing over the years have convinced me of the benefits over traditional designs. But currently I am more concerned with the side view in terms of local flow with the up-wash and down-wash from the wing at different angles of attack. There are some interesting effects, especially with the shorter fuselage designs.

Still standing.
Old 11-08-2004, 10:30 PM
  #18  
daven
My Feedback: (1)
 
Join Date: Dec 2001
Location: Waseca, MN
Posts: 8,456
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Optimal Fuselage Design

Frank, I mean Bob. I'm very interested in your "short" fuze designs. With the very stable Naca 66-012 I'm sure that a shorty can fly very stable. This takes care of weight issues, and obviously much less surface drag area.

The trick is to get the shorty to take off smooth, and fly stable.

I think it can me done.
Old 11-09-2004, 12:58 PM
  #19  
proptop
My Feedback: (8)
 
proptop's Avatar
 
Join Date: Oct 2002
Location: Rome, NY
Posts: 7,036
Likes: 0
Received 2 Likes on 2 Posts
Default RE: Optimal Fuselage Design

Guys, hope you don't mind me butting in for a minute, and asking a question or two? Do you think the flow is seperating aft of the wing or aft of the widest point, where the fuse. "pinches" in? That would cause turbulence and drag, wouldn't it? I was just looking at my plastic model of the Mitsubishi J2M "Jack" (WWII fighter) and the fuse. is convex, kind of like an elongated teardrop, with the widest point about where the cockpit is. Since it's hard for us mere mortals to improve on nature, maybe an elongated teardrop, or perhaps a high speed fish like the Barracuda would make a really nice fuse.? How about a "Flying Fish" style fuse.?
Another part that kind of confuses me is that the prop accelerates the flow along the fuselage, and it's swirling in a helical ring like a corkscrew around the length of the fuse. Guess what I'm saying is that it's very turbulent, and would it be better to "go with the flow" or try to straighten it out (which it would seem, cause more drag)? How much do you think the swirling "corkscrew" straightens out as speed increases? We've got a little "debate" going on in our club, about square corners vs. a rounded fuselage cross section and which is better. Thanks...
Old 11-09-2004, 10:04 PM
  #20  
HighPlains
My Feedback: (1)
 
Join Date: Mar 2003
Location: Over da rainbow, KS
Posts: 5,087
Received 4 Likes on 4 Posts
Default RE: Optimal Fuselage Design

Dave,

The short ones do fly stable, even with a very small tail. That was never the challenge. Your assumption that the take-off is the difficulty is correct. But over the course of multiple iterations, I managed to tame the take-off as well. There are two phenomena present that need to be dealt with.

The first is when you shorten the tail moment, the airplane sits on the ground with a higher angle of attack. If the landing gear is the same size and you move the tail skid forward 8 inches you can see what happens. On the first one I flew, I never knew which direction it would go in the air, as at the launch it would go ballistic to the left one time, and ballistic to the right the next.. After a handful of flights, the conclusion was that it was taking-off with one wing panel or the other stalled. The solution was the addition of a small extension to the tail skid to decrease the angle of attack on the launch. I should note that the tail was mounted 6 inches behind the wing on the first one. Currently I use 8 inches.

The other problem you will encounter is that with the short nose (which you can do now, mine are in the 2” range), is a tendency for the airplane to want to balloon on take-off. You can counter this with down elevator, but I consider that a Band-Aid. An aeronautical fix is to understand what is really going on, and correct that. As I posted before, local flow around the wing is an area that I am currently interested in. In front of the wing, (at least with the lifting section that I use) the air is actually rising from below the chord line to meet the wing. So when the engine, wing, and tail are mounted zero – zero – zero, the air that the prop is working in acts like the engine is mounted with up-thrust. So I counter the effective up-thrust with a touch of down thrust, about ½ degree. As they say, “Your mileage may differ”, so depending on your wing section, vertical location relative to the thrust line, and the fact that you live north of the 45th parallel, you may need to adjust that figure slightly.

You mentioned weight saving, and lower drag. My last fuselage glassed (natural wood finish) with the servo trays installed (plywood), and wing mounted weighed just 6 ¼ oz. before the tail was added. I cut both fuselage sides from a single sheet of balsa, measuring 4” x 36”, giving you an idea of the surface area. Total weight of the airplane with 5 servos and a brass Nelson required an additional 1 ¼ oz. of weight. And this was with the foam core wing skinned with 1/8” top sheeting and 3/32” bottom.

A side note – here is a truly remarkable homebuilt airplane. But to fly it you are betting your life on the engine, as the high stall speed virtually guarantees that any off airport landing is fatal. In fact it did kill the guy selling the kit and a guy that built OEM engines when one of his engines failed. But as it is clever in the methods of cutting drag, I thought I would toss it into the discussion.

Questair Venture

http://www.aircraftpaintschemes.com/...AircraftID=367
Old 11-09-2004, 10:44 PM
  #21  
PylonWorld
Banned
 
Join Date: Dec 2001
Location: Monroe, NC
Posts: 1,332
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Optimal Fuselage Design

Bob,

I've also flown in a metallic burgandy Venture out of Hartsville, SC after a South Carolina breakfast club. 300 knots in a prop plane is truly a trip. I did not fly it, nor was flying it offered to me. That was about 7-8 years ago, and I seem to remember a 120 knot approach crossing the threshold at 90-100 knots.

The web site you listed links for sells paint schemes. Their line drawings are not accurate 3-views. The Glassair III almost looks like a caricature. The nose is too wide.

It so happened that the Charlotte Aeromodelers had their monthly club meeting at a restaurant near Wilgrove Airport where I learned to fly. I stopped in and N4168J, a 150hp 1965 Cherokee 140, had just come in. After catching up with some friends I hadn't seen in a while, I got a good friend by the name of Melvin Carriker to help me measure 68 Juliet. Here's what we got:

Fuselage Width at front of wing: 43"
Fuselage Width at flap hinge line: 44.5"
Fuselage Wicth at trailing edge: 42"

The progression was straight to the flap hinge line, which is where the tail taper starts. I forgot to measure the flap width but it is approximately 8-9". So the wide point on a PA28-140 is almost at the trailing edge. Since the gap at the flaps are a drag source, it doesn't really matter that the wide point be all the way to the rear of the wing.

In terms of the Lancair IV, it was a clean sheet of paper airplane. It borrowed from the 200/320/360 stylistically, but the fuselage was a new design. Just as the Katana DA-40 borrowed from the DA-20 (which I have also flown out of Concord, NC), the IV was not just a stretched version of the prior planes. The 200/320/360 did not have wing fillets, or at the very least they were very small.

In terms of the [link]http://www.aircraftpaintschemes.com[/link] line drawings, have another look at the Lancair IVP. Note that the nose is pointy. That is possibly a top view of the Lancair PropJet, but it most certainly is NOT an accurate top view of a IV or IVP.

I don't mean you any disrespect. I think your experimentation is great. I may even have to try your swept wing planform.

I do want to thank you for indirectly getting back to Wilgrove to see some old friends. I found out that my friend Alan Cobb now owns and runs the FBO. He still has his Seneca (I) and Citabria. And I got offers to go flying. I lost my medical because of medications I was taking for Crohn's Disease. But I am coming off of the FAA offensive drug I was taking, so I should be able to start flying with a Sportsman Pilots license after I get the medical cleared up. And I also found out that another friend who owns an Arrow that I've flown a lot just bought an Aeronca Chief to get some tail dragger time in before he finishes his RV-4 that I also helped on.

My wife has said that I can fly fullscale or models, but not both. But if I get to fly fullscale for free, I may just get a 2 for 1.

OAO

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.