davparlr
Senior Master Sergeant
Unfortunately, I am convinced that You have not yet succeeded to prove this assumption beeing correct.
I have addressed all of these issues in previous post. I will recap succinctly.
How big is the new wing?
The larger wing is the same wing that Hughes used to set his cross country record in the H-1, wing span of 32 ft, 191 sqft area.
What is the difference in drag related to the bigger fuselage?
I estimated a 24 mph reduction in top speed at SL for the increased fuselage diameter
"Install P&W R-1830 (1000 hp), increasing form area by 1.95 sqft and weight by 200 lbs (?).
Airspeed 328 mph SL (weight impact on airspeed negligible) (drag formulas)"
What was the original powerlevel at the H-1´s record flights?
Unknown. For the top speed record it was probably slightly below max output of 1000 hp. Hughes stated that he could go faster so he felt more power could be applied. For the cross country record it was probably at normal rated HP or below, 700 hp?.
Remember, it took basically a simple Bf-109D airframe very little to achieve a low level record speed of 610 km/h. On 11 November 1937 the Bf 109 V13 flown by Messerschmitt's Chief pilot Dr. Hermann Wurster, and powered by an 1,650 hp (1,230 kW) DB 601R racing engine set a new world air speed record for Landplanes with piston engines to 610.55 km/h (379.38 mph) at low level and won the title for Germany for the first time. The V-13´s modification was the Db-601R engine, a special treated surface and the removement of equipment and weapons. Nevertheless, the same Bf-109D but in an operational condition was unable to hit 300 mp/h at SL with a normal rated engine.
The V-13 engine, had a greatly overblown engine that had to be scrapped after the flight. 1650 hp (81% increase) was NOT 'very little'. With 65% more power than the H-1, the specially prepared V-13 was only capable of being 37 mph faster. This really doesn't say much unless you compare the H-1 with 1650 hp. I am sure someone can calculate the theoretical speed of the H-1 with 1650 hp given that it made 353 mph with 1000 hp. Knowing the propaganda desire of Germany, I suspect the Bf-109D was, in reality, highly modified. Remember, the Bf-109R was an entirely different aircraft than the Bf-109.
As far as I know, the H-1´s special engine was also tuned from 700 hp to over 1000 hp, altough the exact powerlevel at the flights are still unkown to day.
The engine in the H-1 was a standard R-1535 engine, as claimed by Howard Hughes, that had been tuned to use 100 octane fuel, a technique used extensively in WW2. Hughes was proud of this. He stated that all the aircraft that had flown faster than the H-1 up to that time, the Supermarine float plane racers, had special short lifetime engines. There is no account that the engine was changed between the high speed record and the cross country record, although it could have been. In any event I proposed the use of the R-1830 engine, a well proven engine used in the F4F and capable of 1200 hp in 1939.
The wing area was just 138 ft^2 in the original design. The adjusted bigger wing area of Your design is around 190 ft^2. This alone translates into 38.5% more wing area.
With a 1200 hp rated engine at Sealevel and the given increase in wing area, my physics show no realistic probability to exceed a speed of 300 mp/h at Sea level. Actually, with this increase in wing area, You would need to pull at least 1330 hp out of the engine to make 330 mp/h at SL plausible. With the same 1000 hp engine, the H-1 would have been hardly pressed to hit 250 mp/h at SL with the bigger wings, everything else staying identical to the H-1 Special. And this does not include the increased drag caused by the bigger diameter fuselage, equipment, raised canopy or gunports. All included, a top speed of ca. 290 mp/h seems more realistic to me (there is some likelyhood that more exhoust thrust may be generated). This also puts the H-1 closer along the lines of the performance drops known from the Bf-109D and Spitfire.
I am not an aero engineer so I must confess lack of expertise, however I am confused by this and how you arrived at the values you did. I think your numbers are low. According to centiennialofflight.com, the percentage of drag of the wing of a Bf-109 is about 37.5% (not including induced drag) of the total drag of the aircraft. The increase of drag due to the larger wing should be compared to the total drag, which would be a less percentage than what you calculated. Also, with an increase of wing span, the level flight induced drag would be less than the short wing version, something I did not try to calculate, it would not be much at high speeds. In addition, on comparing to other aircraft, your large drop in airspeed due to a larger wing does not seem to hold. The Ta-152H with a wingspan of 47'4" and an area of 250 sqft is only about 6 mph slower at SL than the Ta-152C, which has a wingspan of 36'1" and an area of 210 sqft., and roughly the same hp (the Ta-152C actually has more hp). Also, the P-47N with a wingspan of 42'7" and an area of 322 sqft., has the same SL top speed as the P-47M with a wingspan of 40'9" and an area of 308 sqft, and with the identical engine. In addition, the Spitfire has a 37.5% larger wing than the Bf-109, yet both have the same SL top speed with equivalent Hp. I doubt that the elliptical wing could make up that 37.5% difference. Larger wings and more area, in themselves, seem to have minimal impact to these aircraft so I fail to see why it would have had such a large impact to the H-1. Perhaps the discrepancy is due to the way referenced area is defined. Doing a recalculation based on separate impact to the wing and fuselage and then to the overall drag, I came out with a number higher than my original. But, considering my level of intellect on drag, (it gives me a headache) I'll still stick with my original numbers.
tommayer said:Dick Palmer, principal designer of the H-1, was a family friend. I knew him fairly well, talked to him at length about the H1. He told me the bird was almost ready to fly before Hughes let him know that he, Hughes, was going to fly it. Dick was worried. He thought Hughes was competent enough, but it was a new design, and Hughes was signing the pay checks, so Dick both assumed and hoped Hughes was going to have a professional test pilot do the flying.
I asked him if it was a difficult or dangerous plane to fly. He thought not. Especially with the X-country long wings. He specifically said stalls were NOT violent, abrupt or in any way unusual.
Wow. I would have loved to talk to him. I think the H-1 was a fascinating aircraft and I have a lot of questions about it he would have been able to answer, namely everything we have been trying to answer here.
I also asked him if the H1 could have been made into a military airplane. Answer: "That was the idea."
This was my assumption. And, I think Hughes would have built a high performance fighter.
I've always thought the H1 may be the most beautiful machine of any kind ever made by anyone. I have spent many hours just looking at in the old Smithsonian. I was sorry I never got to see the Wright replica, and even sorrier that it and Wright crashed.
My feelings too!
Clay_Allison said:Let me re-phrase my question. What if the H-1 had been designed around the Allison V-1710 from the very beginning? Less frontal area, potentially an even cleaner airframe. It would have been a much better prospect for a fighter if it already had a desirable power plant, rather than the need for an iffy engine swap that would have unpredictable results.
With the lines and the shape of the plane already determined, all that would remain is stressing it, putting a standard Allison (rather than an overboosted racing engine that might have been pushed to 1600 horses for the speed record) in it and hanging guns, armor and self sealing tanks on it, the exact same process that the Spit and the 109 had to go through.
Sorry to divert your thread. The V-1710 would have added several hundred pounds to the H-1 and therefore some maneuvering impact. There is no reason to believe that the H-1 could have been built to the weight of the Spitfire. The more slim design could have aided the top speed. If we look at the Vultee Vanguard prototype and the P-66, we could get a glimpse of what performance change could be obtained. The P-66 was designed by the same man who helped Hughes with the H-1 (see tommayer entry above). It was bulkier, however. The Vanguard was the basically the same plane with a streamlined fuselage covering an R-1830, both had the same engine. The top speed of the P-66 was 340 mph and the top speed of the Vanguard was 358 mph. It is apparent that the V-1710 most likely would have improved the H-1 max speed, but it would have had the same altitude problem as the P-39/40.