FASTER, FASTER, FASTER!!! (010200)
From: Steve Wetherbee <wasinc@northpro.net>
Monty, Some more Swift questions: Do you or someone in the organization have any lists of other speed mods both approved and unapproved and as to how much speed is gained for each mod? We are thinking about the flap gap seals, are they worth the no paperwork risk? How about a retractable tailwheel? I have closed up the tailwheel opening but haven’t flown it since. This one also has stock wingtips, I like the looks of them but wondering about why people take them off? I also was going to go to the sliding canopy but sounds like no one knows what happened to the guy that now has the STC. Do you know anything about that. One more what can be done to move or go to a electric trim? Steve
Steve:
I don’t think gap seals do any good. A retractable t/w may help if you’re in the 180 mph range — but below that I don’t think you’d, notice any difference. I don’t know what’s going on with the canopy STC — electric trim is included in the canopy STC. Read the links from the Swift Home Page. The stock tips are the best, the Bonanza tips really cut down on the r/c altho they may be a tad faster. Mostly the stock tips get removed because of cosmetic reasons — they get dented up. I have copies of one-time field approvals for electric trim. Some of the biggest “speed secrets” are to tighten up the wing bands (tape underneath) and put seals ahead of the elevators/rudder and above the flaps/ailerons (like foam seals) to minimize air movement thru these areas. After you get up to, say, 160K or 180 mph it gets harder and harder to gain more. You can always try to reduce the empty weight. Read the Home Page for STC’s available. — Jim
“STRIP SHOW”… (010300)
Subject: Re: Swift speed
From: wasinc@northpro.net
Monty,
Flew the swift late this afternoon both double occ. and solo but pretty full of gas, the side to side yaw seems to be gone and airspeed shows 185 at 25/25 Gps showed about 178, did notice that the wing to center section straps were flying” pretty good even though we just tightened them today. What is the best way to hold them down flat. You also mentioned foam between ailerons/flaps and tail surfaces, could you explain that in more detail like what kind of foam. Is this air pressure in the wing making those strips fly up? and the foam blocks some of that? Temp was about zero so speed could be from that difference since last flight of 28 degrees. I just bought a digital camera so when I figure it out I will send you a picture. Steve
Steve,
The gap strips “flying up” are one of the biggest potential drag producers on the Swift. That area has a really low pressure, I’ve had them so tight you could hardly pry them up, and the next flight they rode up considerably. With them off, tape up the gap between the wing and center section, the reinstall the gap strip. You can even make the upper surface of the gap strip semi-permanent by application of some sealant, (over tape) they vary somewhat, sometimes you just have to install some screws to hold them down. The foam seals I mentioned can be made out of common hardware store foam that they sell for insulating doors, windows etc. (3M or whatever) They sell it in rolls, 3/8″x 1/2″ or whatever fits between your wing upper trailing edge and the aileron or flap. It is best installed with the surface off with contact cement. — JM
IT ALWAYS GETS INTERESTING WHENEVER MEN DISCUSS SHORT VS LONG… (010400)
From: “Dot & Bill Shepherd” <billdot10ss@prodigy.net>
Subject: more on wingtips
To add more fuel to the fire on Short vs. Stock wingtips, here is some results on my Swift . These tests were done back when I had a 150 Lyc. When I first put the short tips on I found climb rate was down considerably at 85 MPH. So I switched back to the stock tips, then noticed that climb time to cruise altitude was no better than with short tips! I switched back to the short tips and did more thorough climb tests and found that at my normal climb speed the rate of climb was the same. At about 100/105 and above I could not measure any difference in climb rate using a stopwatch and altimeter. Also even more interesting, was no difference in stall speed. Switching to short tips you loose a fair amount of wing area, so what is going on! After pondering this for a while I talked with a friend who was pretty deep into aerodynamics and his explanation was that shorter aspect ratio wings with the same airfoil stall at a higher angle of attack, thus producing more lift per sq. ft. of wing area (and more drag) at that angle of attack. The absolute ceiling will be reduced with the short tips-but only when the climb or cruise airspeed (indicated) drops to 105MPH. Other benefits of short tips are faster roll rate, takes up less hangar space, and one other neat surprise-shorter landing rollout. How can that be! The lower aspect ratio wing hasless ground cushion and the tires don’t skip along as much after touchdown and allows you to start braking sooner if needed. I noticed this when switching the tips back and fourth during testing. One last comment, a good set of stock tips is much prettier. — Bill
(Editor’s note: My lovely bride Erin has a nice set of short wingtips on her Swift that she would LOVE to trade straight across for a pair of stock tips. In fact, I’ve got an extra set of short tips in storage too! Any takers???)
KIND-OF A DRAG… (010500)
From: Bill Harris <Temcowilly@aol.com>
Subject: Re: January #4 GTS Internet Update
For your info – Kent Koester years ago went thru the Stanford research library which had W W 2 ‘s Moffett field wind tunnel data on drag on everything you could think of. The venturi ( large ) at 120 mph took 6.5 hp to drag it thru the air. Bill Harris
THE NEXT BIG THING: RETRACTABLE PITOT TUBES??? (080300)
Subj: Fwd: Speed
From: Jerry Swartz <JSw7211963@aol.com>
<< Here’s something to think about. Some fellows found that removing the pitot tube from an RV increased the speed by 4 mph, so they are making it retractable!!! >> Now here is something you could market, Jim. Use the GPS for cruise altitude and the pitot for pattern altitude. Jerry
Jerry,
We-e-ll, many Swifts have been modified with a pitot directly out of the leading edge of the wing. (no drag) All that was different was the airspeed indication was not very accurate! — Jim
CHANGING THE PITOT TUBE IS NOT THE ANSWER… (080300)
Subj: Re: Speed
From: Jerry Swartz <JSw7211963@aol.com>
Jim
Have patience!!! Someday I may catch up, but don’t plan on it. Wouldn’t give up my original pitot for ten mph more speed. Not that many of them left around. Jerry.
Jerry,
Changing the pitot tube is NOT the answer! A bogus pitot tube may well give an indication of 150 mph cruise, but the airplane is not going any faster! The easiest and most legal way to increase speed is to run the CG at the aft limit and get a Sensenich Prop. — Jim
