Hughes H-1 Racer replica speed record attempt

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This is going to sound silly, but
  1. What diameter is the H-1's propeller? That thing looks huge
  2. How much did Hughes overboost the engine to? I know it was over 1000 HP, but I'm not sure by how much
  3. Could it actually fly 4000 miles or was that a mistake?
 
1. Do not know
2. Not a clue.
3. Not a chance.....

The H-1 had two sets of wings - one for setting the speed record (at 352mph it was the fastest land plane in 1935, but 90mph slower than the Macchi MC72) and one for cross-country flights.

Hughes set the transcontinental record (2,500 miles) with the H-1 with the long span wings, with a non-stop flight.
 
Could it actually fly 4000 miles or was that a mistake?
Hughes set the transcontinental record (2,500 miles) with the H-1 with the long span wings, with a non-stop flight.

The record was set from west to east which was a common practice in the 1930s as all of these race/record setting pilots were well aware of the prevailing winds blowing over the US from west to east. Hughes himself had flown as a co-pilot in a commercial airliner 5-7 times (?) on west to east trips to try to check out the situation. he was also planning to fly at around 20,000ft for the whole trip while using oxygen to really take advantage of the tail winds but a malfunction of the oxygen system forced a lower cruising altitude.

East to west flights sometimes required a fueling stop.
 
1. Do not know
If I presented you some images, could you determine which one best represented the aircraft's proportions best?
2. Not a clue.
Do you know anybody who would?
The H-1 had two sets of wings - one for setting the speed record (at 352mph it was the fastest land plane in 1935, but 90mph slower than the Macchi MC72) and one for cross-country flights.
Do you know what effects the wings had on the maximum speed?
Hughes set the transcontinental record (2,500 miles) with the H-1 with the long span wings, with a non-stop flight.
So 2500 miles would be a very basic starting point...

The record was set from west to east which was a common practice in the 1930s as all of these race/record setting pilots were well aware of the prevailing winds blowing over the US from west to east. Hughes himself had flown as a co-pilot in a commercial airliner 5-7 times (?) on west to east trips to try to check out the situation.
Do you have any idea how much tailwind the aircraft would have been facing? I'm curious if that can be used to somehow gauge a still-air range.
he was also planning to fly at around 20,000ft for the whole trip while using oxygen to really take advantage of the tail winds but a malfunction of the oxygen system forced a lower cruising altitude.
Did he use a different supercharger gearing arrangement for the low/high altitude flights?
 
I have a drawing of the H-1, attached.
H-1.jpg


I talked to the people at the Smithsonian who restored the airplane. They wanted to display it with the short wings, but while they had them available as well as the long wings already installed on the airplane, they found it was not a simple process and the airplane would have to be rebuilt to do that.

The original used a skid rather than a tailwheel and rebuilding that after it had been used on a hard surface runway was a real chore. The replica used a tailwheel.

Flush rivets had not been invented yet so each round headed rivet was ground down to make it flush after installation.

There is another replica H-1 that was displayed alongside the Spruce Goose but I assume it was a nonflying example.

A friend of mine heard that the H-1 was sitting around an airport in NJ, Teterboro, I think, and that the airport management was tired of having it around and was going to have it scrapped. He got hold of Walter J Boyne and as a result the Smithsonian got it.
 
Flush rivets had not been invented yet so each round headed rivet was ground down to make it flush after installation

Doesn't sound tight - if you grind the head down flat on a round headed river, there's no head left to hold the panels together. You could conceivably grind the chamfer in prior to installation, and hen flatten the resulting head I guess, but there'd be a lot of variation in rivet strength.
 
I looked at them closely, The rivets have indeed been ground down and then then surface highly polished. There is just a "smear" where the rivet is. This was not like drilling out a rivet. The action of carefully grinding away each head tends to cause the rivet and the skin to blend together. I have even drilled out the head of a rivet and found the parts were still stuck quite firmly together, the shank being stuffed very tightly into the hole in the skin.

Remember that this airplane was not designed to last very long, and after it had done the job Hughes more oe less threw it away.
 
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I have a drawing of the H-1, attached.View attachment 537995
That is quite a difference in wing-area too... the propeller diameter doesn't seem all that big in that image. Still managing 332 mph for 7:28:10 is pretty good. I'm not sure what the typical tailwinds across the country are when flying at 10,000 - 20,000 feet. From what I remember they form at around 4 - 8 miles high.
 
As I recall, when the Smithsonian went to assemble the H-1 for display, they found the tolerance for mounting the wing to fuselage was so close the fuselage and wing had to be at the same temperature to fit together. I don't remember what the temp/humidity was for it to fit. As for stuck rivets with heads ground off, I can agree at least as far as 51-52 chevy transmission cross member goes. I can't remember exactly but I think it was something like 18 rivets and the heads had to be drilled slightly below level and a punch and heavy hammer used to drive the rivet through.
 
As far as how did the engine achieve overboost, usually at sea level where the speed record was achieved, overspeeding of rpm is done. Since the propeller was ruined in the belly landing after the speed record, it is probably not in existence to measure, but a smaller length blade may have been used to make best use at a 10% overspeed. These engines are not too sensitive to overspeeding as far as lack of reliability but it does raise torque and horsepower, as the rpm increases blower rpm and manifold pressure, by increased BMEP. This could be done with a stock supercharger gear, probably most efficient for sea level operation.

The ground down brazier head rivets story I have never heard though it sounds like a line from the old Tommy Lee Jones movie. I recall that tooling was made to make countersink fasteners for the project, as well those tools may well have been on the drawing board or available owing to Seversky, Douglas, Lockheed and Curtiss airplanes a year later had at least partial airframe flush riveting. Besides, if a round head rivet were ground flush it would no longer have anything to hold the stem to the perpendicular sheeting because it would be gone! Funny premise...

The Teterboro story sounds like a carry over from the Charles Blair Mustang rather than the H-1. Glenn Odekirk flew the airplane back to Hughes Culver City soon after the record flight. I was a most disappointed teenager when I was not allowed to go see the airplane at the huge hangers at Hughes Field when it was being readied for shipment to Washington for display in 1975. I was presented a couple of nice 8x10's of it in the 30's by Harry Gann, though I cant remembering if he and his photo buddies were allowed in either.

I witnessed the record attempt at Reno and the prop, by its sound, was at it's tip speed limit at the power and rpm they were using. At 305 mph, at 5050 foot field elevation, especially at the cool temps that morning, it seemed this blade length was too long for a faster speed. It sounded much like a T-6. By comparison, one would see up to 5 to 10 mph increase in speed for the altitude for the same configuration as the 1935 record.

The A-17 attack plane prop used on the Wright replica was just too long for any more speed, but a fine set-up for cruising. Too bad that that same propeller's counterweights weren't machined to prevent them loosening and moving in normal operation which ultimately led to the Jim Wright fatal accident... as well as flight planning over hostile terrain as if it were a multi engined jet. People do it all of the time, but I do not. My dad set me straight as a kid, follow the highway that way if the forced landing doesn't go off too well some passing motorist might come over and drag you out!

Chris...
 
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I have looked at the real H-1 and talked to the people doing the restoration for the ASM and I can assure you that the rivets were ground down. Go look at it yourself and talk to the restoration people. And if you believe that grinding the head down completely destroys a rivet's ability to secure the skin, then you have never tried to drill out a aircraft rivet, but I have numerous times.

By the way, there is essentially a modern version of the process, called Friction Stir Welding. The Falcon 9 rocket is built using that.

As for the Teterboro story I am sure that my friend was not lying to me - and he was one of the people involved; it was not a story he heard in a bar.
 
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