Is it any chance to fly 62 lb for each horsepower?

S

simplex1

Ejection Handle Pulled
Joined
May 22, 2014
Messages
90
Display Name
Display name:
simplex1
Is it any chance to fly 62 lb for each horsepower at a speed of 38 mph?

Supposing someone wants to build a small plane (it can be radio controlled) with a total weight ranging between 62 and 1000 lb, is it any chance to fly it at 38 mph using an engine that has a power equal to the total weight of the plane, measured in lb, divided by 62 lb/HP?
 
Last edited:
I have no idea if it's theoretically possible, but I did lookup a Piper Cub, which is about as basic and slow of a plane as you can find:

Max takeoff weight: 1220lb.
Engine: 65 HP
Lb/HP: 18.7

You'd be doing the equivalent of flying a Piper Cub with a 19HP engine. I don't see it happening.

edit: Wikipedia lists the Wright 1903 Flyer as 50lb/HP. That's close... I don't know how it scales with mass, though.
 
Last edited:
I'd have to go digging into my aero texts and doing some math to answer that with reasonable analysis. but my gut feel is "no".
 
Probably not as small as you would like.
Solar Impulse weighs in at 3500 lbs and is powered by 4 10 hp motors
Cruises at around 40 knots.

So not a small plane but possible.
 
I have a feeling this conversation is headed the same way as his dissertation on the Wright Brothers. :popcorn:
 
Yes, solar impulse is above 62 lb/HP. Unfortunately it is too large and heavy.

Wingspan-of-Solar-Impulse.jpg
 
simplex1 said:
Is it any chance to fly 62 lb for each horsepower at a speed of 38 mph?

Supposing someone wants to build a small plane (it can be radio controlled) with a total weight ranging between 62 and 1000 lb, is it any chance to fly it at 38 mph using an engine that has a power equal to the total weight of the plane, measured in lb, divided by 62 lb/HP?
Click to expand...
Yes. "How," is an exercise left to the reader.
 
Take, for example, the ostrich. He weighs several hundred pounds, but flies fast enough to catch his prey (koala bears, which are not really bears) on much less than one horsepower (compare the size of an ostrich to the size of a horse).
 
Lindberg said:
Take, for example, the ostrich. He weighs several hundred pounds, but flies fast enough to catch his prey (koala bears, which are not really bears) on much less than one horsepower (compare the size of an ostrich to the size of a horse).
Click to expand...
The ostrich may run that fast (near 45 mph dash and over 30 mph sustained), and if you saw one moving across the ground at that speed you might say, "Boy, that bird is flying!". However, it cannot fly as in "maintaining itself in wingborne flight with no ground contact" which is, I think, what we are discussing here.
 
Lindberg said:
Take, for example, the ostrich. He weighs several hundred pounds, but flies fast enough to catch his prey (koala bears, which are not really bears) on much less than one horsepower (compare the size of an ostrich to the size of a horse).
Click to expand...

:rofl::rofl::rofl: You caught one...:lol::lol::lol: I'd be surprised if anything could fly slow enough to catch a koala, them suckers cause a 2 mile traffic jam when they cross the road..:D;) Maybe a flock of hummingbirds with a net...:idea:
 
Ron Levy said:
The ostrich may run that fast (near 45 mph dash and over 30 mph sustained), and if you saw one moving across the ground at that speed you might say, "Boy, that bird is flying!". However, it cannot fly as in "maintaining itself in wingborne flight with no ground contact" which is, I think, what we are discussing here.
Click to expand...
I think he meant to say penguin, not ostrich

Sent from my Nexus 7 using Tapatalk
 
How the hell is the koala bear the prey of an ostrich? Ostriches aren't even Australian animals.
 
simplex1 said:
Is it any chance to fly 62 lb for each horsepower at a speed of 38 mph?

Supposing someone wants to build a small plane (it can be radio controlled) with a total weight ranging between 62 and 1000 lb, is it any chance to fly it at 38 mph using an engine that has a power equal to the total weight of the plane, measured in lb, divided by 62 lb/HP?
Click to expand...

This sounds remarkably like a homework assignment...
 
simplex1 said:
Is it any chance to fly 62 lb for each horsepower at a speed of 38 mph?

Supposing someone wants to build a small plane (it can be radio controlled) with a total weight ranging between 62 and 1000 lb, is it any chance to fly it at 38 mph using an engine that has a power equal to the total weight of the plane, measured in lb, divided by 62 lb/HP?
Click to expand...

Given a long rough runway, sure, I bet you that the Condor was even a bigger spread. What does a human put out for HP?
 
Probably varies human to human.
Wikipedia says "a healthy human can produce about 1.2 hp briefly"
 
MIT Daedalus fits the parameters

Sent from my Nexus 7 using Tapatalk
 
SixPapaCharlie said:
probably varies human to human
Click to expand...

Well, they used athletes to fly it, and they weighed over 100lbs I'd think, not sure what the rig weighed but I doubt less than 20lbs. So there's 120lbs. 1hp is about 750watts, I used to have a pedal generator and there was no way I was producing 750 watts, probably lucky to be producing 250 watts which is what, 1/3rd of a HP? That Condor rig was about as efficient as it gets, and light.

The key is long, high aspect ratio wings, but yeah, I bet you could make a good motor glider work at 62lbs/HP.
 
He's back! Don't get sucked in to this posters agenda.

The Wright Bros. 1903 Flyer weighed 605 lbs empty, 745 lbs with the pilot and had a 12 hp motor.

745/12 = 62 lb/hp

Remember, Thrust only has to overcome Drag, it has nothing to do with Lift.
 
Last edited:
One thing that IS useful is this relationship. A gasoline engine like small airplanes have makes 12 horsepower per gallon per hour. What does that mean? Well if you are burning 10 gallons per hour, you are producing 120 horsepower. Now you know your percent of max power (120/180 = 67% power). Etc.

Comes in handy sometimes.
 
what's the power to weight ratio of a zeppelin ?
 
62lb African Swallow or 62lb European Swallow?
 
Cruiser said:
He's back! Don't get sucked in to this posters agenda.

The Wright Bros. 1903 Flyer weighed 605 lbs empty, 745 lbs with the pilot and had a 12 hp motor.

745/12 = 62 lb/hp

Remember, Thrust only has to overcome Drag, it has nothing to do with Lift.
Click to expand...
The 1903 Wright Flyer fell short of 38 mph -- top speed about 30 mph, IIRC.
 
For proper context, the OP is trying to prove that the Wright's lied about their pre-1908 flights based on a French story that reports an MTOW and engine HP that yields "35 pounds/HP", whereas the earlier December 17, 1906 edition of Scientific American mentions a more impressive "62 pounds per horse-power":

wright_hp.jpg


The OP alleges that the Wrights lied about the pre-1908 flights because the number couldn't have dropped from 62 to 35 lbs/HP from 1906 to 1908:

http://www.pprune.org/aviation-hist...ded-1903-they-flew-1908-a-26.html#post8527713

We all now how reliable journalist are about all things aviation.

By the way, can anybody make sense of the last sentence, the one right after the yellow-highlighted one?
 
Last edited:
register@teamandras.com said:
For proper context, the OP is trying to prove that the Wright's lied about their pre-1908 flights based on a French story that reports an MTOW and engine HP that yields "35 pounds/HP", whereas the earlier December 17, 1906 edition of Scientific American mentions a more impressive "62 pounds per horse-power":

wright_hp.jpg


The OP alleges that the Wrights lied about the pre-1908 flights because the number couldn't have dropped from 62 to 35 lbs/HP from 1906 to 1908:

http://www.pprune.org/aviation-hist...ded-1903-they-flew-1908-a-26.html#post8527713

We all now how reliable journalist are about all things aviation.

By the way, can anybody make sense of the last sentence, the one right after the yellow-highlighted one?
Click to expand...
Plug those numbers into the yellow highlighted sentence.
 
This again???

This seems like a good place to increase my post count then
 
The answer is simple, really. That was an age of draft horses pulling farm implements. The horses were bigger.

in all seriousness, the wright 1903 was capable of flight. It was not capable of takeoff of climb, it could barely sustain flight after a towed launch. That's a far different idea of power per weight than what we think of with a piper cub etc.
 
Last edited:
coloradobluesky said:
One thing that IS useful is this relationship. A gasoline engine like small airplanes have makes 12 horsepower per gallon per hour. What does that mean? Well if you are burning 10 gallons per hour, you are producing 120 horsepower. Now you know your percent of max power (120/180 = 67% power). Etc.

Comes in handy sometimes.
Click to expand...
The relationship between FF and HP varies considerably with mixture and to a lesser extent compression ratio. My engines get about 10 HP/gph at full power with a full rich mixture and close to 15HP/gph in cruise flight.
 
EdFred said:
Plug those numbers into the yellow highlighted sentence.
Click to expand...

OK. And, reordering from slowest to fastest, you get:


At 20 miles an hour, they could sustain 125 lbs/HP
At 38 miles an hour, they could sustain 62 lbs/HP
At 75 miles an hour, they could sustain 30 lbs/HP

I still don't quote follow what this means. Do you?
 
Hawka said:
define "briefly".

1 millisecond maybe?
Click to expand...
I've managed to hit 1 HP (744W) on an eliptical exercise machine for a lot longer than 1ms. These days (63 yr old body) I can't do that for more than 15-20 seconds though, perhaps that's what "briefly" means in this context.
 
You must log in or register to reply here.
Back
Top