Author Topic: minimum flying speed  (Read 8604 times)

Doug Johnson

minimum flying speed
« on: July 19, 2011, 06:32:06 PM »
I was looking at the Helio LLC site and saw the figure for new Helios min speed as 28 knots. It got me to thinking about Helio slow flight speeds. Larry Montgomery told me or probably Tony larrys flight instructor that the Helio minimum flight speed was 35 knots about 40 mph. Larry even had it printed on the T-shirts he gave away.

I fly a Kasperwing ultralight that will fly at 27 miles per hour with a 195 lb pilot 25 mph with a 140 lb pilot and this was verified with a police traffic radar gun. So I am quite familiar with slow flight. I  know the Helio H-295 with just me and 60 gallons of fuel flew comfortably at, at the least 40 mph. Maybe a light H-395 might fly slightly slower. I don't know. When I did a full stall power on landing I would imagine I was at probably slightly below 35 mph but that's the only time I was much less than 38-40mph.

I have read these 30 mph figures so many times I thought I would post a few of the times I've seen this repeated.  Brandon T. Buerge seems to come closer than anyone to realistic figures.

1)        Brandon T. Buerge While credit in the popular aviation media for the incredible lowspeed performance is normally given to the slats, the author's own analysis indicates that it is due also to two other factors rarely considered.

          The first is simply that the airspeed indicator errors are large (>50%) at low speeds, giving pilots the impression that the aircraft performs more impressively than it does. The actual minimum control speed is probably around 37 knots under full power rather than the often-reported 22 knots' 
25.32 MPH (US Air Force 2001).

         The second is that the unusually large propeller  (8' diameter 3-bladed propeller  vs.  6' 8”  3-bladed propeller installed on the Cessna C-185, a similar utility aircraft, allows the aircraft to generate tremendous thrust at low speeds. In combination with the slats, that allows the aircraft to reach unusually high angles of attack, the large propeller ends up generating a very considerable vertical component thrust which significantly reduces the weight that must be supported by the wings at low speeds. According to the author's calculations, in level flight this reduction can be well over 20%. This serves to reduce the minimum control speed to below the range of more conventional aircraft.

2)        The unique wing design calls for a different technique on landing. The large wing is a laminar flow design (actually the same profile as the P-51 Mustang). The slotted Fowler flaps and automatic Handley Page leading edge slats increase the wing area by about one third. It's possible to maintain altitude at 28 mph, however your CHT will climb rapidly and the deck angle is pretty steep. You are hanging on the prop. You can turn the airplane pretty much in it's own wingspan at this speed.

3)         The Helio Courier, which has the ability to take off and land at 30 mph on unimproved landing strips less than 500 feet long, has established itself firmly in the general aviation market. A certificated STOL (Short Take Off and Landing) aircraft, the Courier series displays an aptitude for safe, almost stall-proof, slow-speed flight.

4) SPEED Minimum, Fully Maneuverable S.L. 26 knots      (Helio LLC  specs. for h-295)

5) Frank Rowes book

H-391B   H-250   H-395   H-295/HT-295   H-700   H-800 Minimum SpeedPower On (mph)
30           31        28         30                      51       52

6)Smithsonian write up on helioplane
 
The successful first flight was on April 8, 1949. While the Helio-1 had a top speed slightly faster than the Vagabond, its slow speed capability of 30 mph was far superior to any fixed wing aircraft available at that time.

7) HelioCourie.net Successor, Helio Couriers, used identical high lift and control devices to make short takeoffs and landings (under 40 mph) practical under operational  conditions.
« Last Edit: October 30, 2011, 09:27:24 PM by Doug Johnson »
Doug

greatlakeshelio

  • Guest
Re: minimum flying speed
« Reply #1 on: July 20, 2011, 08:29:43 AM »
In response to Frank Rowe's book on minimum speeds for the H700, there is no way you are going to get that heavy John Deere garden tractor down to 31. You are limited in stabilator travel for one, 10 degrees less travel than the 295 due to it's gross weight. Two the 700/800 airplanes have stall suppression indicators that were required during certification.

The Helioplane flew at 26.5 MPH before full throttle was realized and that was dead accurate number because it was timed and calibrated.

Doug Johnson

Re: minimum flying speed
« Reply #2 on: July 20, 2011, 01:47:10 PM »
I went back and modified the post to maybe reflect what you said.

I did a check after you brought it to my attention I copied the minimum speeds from a source that quoted Frank Rowes book he had 51 for the 700 and 52 for the 800 another error and I repeated it.

I'm sure you're correct about the Helioplane and I bet the 8' slow speed prop and light weight had a lot to do with it .

And I'm sure sure you are correct about the IO-540 powered H-700 "Garden tractor".

I threw them in as much for comparison as anything. I just find the numbers for the others are differ so much and are awfully low based on my own experiences.

I believe that people are repeating numbers without proper comparison and investigation.

Do you believe this to be the case?

Doug
« Last Edit: July 20, 2011, 04:10:19 PM by Doug Johnson »
Doug

greatlakeshelio

  • Guest
Re: minimum flying speed
« Reply #3 on: July 20, 2011, 03:15:07 PM »
The Helio H700 has the TIO-540-J2BD (350 HP) same as the Navajo Chieftain and it is not a geared engine.

Lycoming once made the IGO-540 (350 HP) primarily for the Aero Commander 560F

Doug Johnson

Re: minimum flying speed
« Reply #4 on: July 20, 2011, 03:53:39 PM »
The GO-540 thing was from not proof reading I'll edit that I meant IO-540 you'd have probably corrected me on that too.

But speaking of the GO-540 what was the outcome of David Maytags tests with IGO-540 with the 106" prop? He seemed enthusiastic about it in 1995.

My real question was that I believe that people are repeating numbers without proper comparison and investigation.

Maybe some of it is improper proof reading too. Its just that there are so many errors in the Helio information available.

That's what I really wanted an opinion on.

By the way I disapprove of the comparison to John Deere tractors I own and prefer John Deere tractors. Although I have to admit when it comes to garden tractors it probably is a legitimate comparison I have one of those too and it was almost a gift from the John Deere Dealer.
« Last Edit: July 20, 2011, 04:17:45 PM by Doug Johnson »
Doug

greatlakeshelio

  • Guest
Re: minimum flying speed
« Reply #5 on: July 20, 2011, 05:54:01 PM »
I'll refer to the Helio H800/700 as flying dump trucks then...as for aesthetics they do like look like a goat.

I contacted Lycoming when I was pursuing the assets and they would build the IGO-540 for $63,500.00 with the deposit set at 100 airplanes. In 1987 I had that many orders with deposits.

Doug Johnson

Re: minimum flying speed
« Reply #6 on: July 20, 2011, 07:53:30 PM »
Stephen,
Wouldn't it be great though to take all 19 of the H-700/800's and put at least the 295 GO-480 or IGO-540 with the 106' prop and 295 landing gear in them get rid of 700lbs put Hoerner wing tips on them and turn them into 4000 lb gross weight Helio's. We wouldn't have to dis any of the Helio's we care about. Let's dream on.

100 airplanes that's amazing I hope that was figuring the percentage of cancellations that always happen. I thought about a restart on Helios a lot, I've always considered them a very specialized expensive niche type specialty airplane with a realistic build number of 10 or 12 per year. With the occasional fleet order of another 10 or 12 but not to be depended on. Enough to support a medium sized FBO type manufacturer out in the sticks somewhere maybe Canada or Alaska where taxes and expenses would be tolerable.
 
That's where I've always thought David Maytag and LLC was going wrong. I don't think its possible for Helio to every compete with Cessna or the other manufacturers one on one. They have to accept the niche market for C/STOL even if they moved up to twins and commuters aircraft.

Doug
« Last Edit: July 20, 2011, 08:04:10 PM by Doug Johnson »
Doug

greatlakeshelio

  • Guest
Re: minimum flying speed
« Reply #7 on: July 20, 2011, 08:18:25 PM »
The only reason Maytag bought Helio was for the Stallion..and guess what?? There ain't no tooling for that, no jigs, dyes, presses, just drawings..

I've personally seen all that.