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Dean

Dean

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Dean
Can anyone tell me how a manufacture comes up with the gross weight of an airplane. What is it based on most, engine HP, wing surface or a combination of both? I have a C150 with 100HP, another 150 here is 150HP, both are rated 1600lbs GW. It is not much faster than mine, but uses 3gph more fuel, so what is the advantage of the extra 50hp if you can not carry more weight?
:confused:
 
The extra horsepower will dramatically increase the aircraft's ability to climb.

Len
 
Dean said:
Can anyone tell me how a manufacture comes up with the gross weight of an airplane. What is it based on most, engine HP, wing surface or a combination of both? I have a C150 with 100HP, another 150 here is 150HP, both are rated 1600lbs GW. It is not much faster than mine, but uses 3gph more fuel, so what is the advantage of the extra 50hp if you can not carry more weight?
:confused:
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It didn't come from the factory like that.

It is for climb & speed, But you don't get much more of either.

A 150 hp In a 150/152 can tow a banner, The 100 cannot. Prolly 10 kts faster, 300 FPM more climb

Sometimes when you put in a bigger engine, you can carry more. It depends on the STC.

As far as factory, I am sure all & everything comes into play.
 
Last edited:
More horsepower, when compared to the stock aircraft, will be available at altitude and in high density altitude situations.

Len
 
Dean said:
Can anyone tell me how a manufacture comes up with the gross weight of an airplane. What is it based on most, engine HP, wing surface or a combination of both? I have a C150 with 100HP, another 150 here is 150HP, both are rated 1600lbs GW. It is not much faster than mine, but uses 3gph more fuel, so what is the advantage of the extra 50hp if you can not carry more weight?
:confused:
Click to expand...

The main difference in the performance of the two planes is the increased rate of climb.

The determination of MGW is complex. It has to do with the plane's ability to perform to certain standards at the max weight. As but one example, single engine planes must have a Vso under 60 knots? 62 knots? I am not sure of the exact number but if the plane will stall at speeds above that, they reduce the MGW until the plane can perform. Or redesign the wing and/or flap system. So, unfortunately there is no easy answer to your question. :dunno:

-Skip
 
Len Lanetti said:
The extra horsepower will dramatically increase the aircraft's ability to climb.

Len
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It will also take off in about 3 feet, and is scads of fun to fly. On a practical side, if you want to use one for banner towing the extra power would be nice. FYI, the C150/152 are certified in the utility category, with no certification in the standard category. If they had certified it in the standard category also, like they did with the C172, it could have a higher gross weight because the G loads are lower in the standard category. I hear from reliable sources that the 150/152 will get off the ground and climb even when overweight by 75-100 pounds. Obviously, I have no first hand knowledge of this, and certainly don't recommend it. I do note that the Piper Colt, with a similar empty weight and the same engine, has a higher gross weight.
 
Dean said:
Can anyone tell me how a manufacture comes up with the gross weight of an airplane. What is it based on most, engine HP, wing surface or a combination of both? I have a C150 with 100HP, another 150 here is 150HP, both are rated 1600lbs GW. It is not much faster than mine, but uses 3gph more fuel, so what is the advantage of the extra 50hp if you can not carry more weight?
:confused:
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Speed and climb performance (the 150/150s are pretty nice in high altitude environments and if you need 10-15 more kts for utility) as well as using a Lyc 0-320 rather than a Cont O-200. There are also structural limitations on the spar and other airframe components which effect gross weight.
 
The 150hp C150 was an old float plane and yes it climbs like crazy. For the 150 being able to carry over GW, I am 205 lbs and my instructor was 200 lbs, plus full fuel, should I say more?
 
Dean said:
The 150hp C150 was an old float plane and yes it climbs like crazy. For the 150 being able to carry over GW, I am 205 lbs and my instructor was 200 lbs, plus full fuel, should I say more?
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I took my checkride in a 152. I am 220. The DE was 210.

At his desk during the oral, I asked him if he wanted me to do a W&B or should I just go see if a 172 was available.

He said. "I did the w&b, We are ok.

I said No I am sure we are not ok.

He said there is no 172 available & he'll take PIC for the W&B.
 
Eamon said:
I took my checkride in a 152. I am 220. The DE was 210.

At his desk during the oral, I asked him if he wanted me to do a W&B or should I just go see if a 172 was available.

He said. "I did the w&b, We are ok.

I said No I am sure we are not ok.

He said there is no 172 available & he'll take PIC for the W&B.
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Mine told me it was fortunate he'd been dieting, because he just lost 10 pounds. Happy coincidense, so had I!! That and having precisely 12 gallons of gas on board made us legal.
 
In most cases, you have no idea which of the two basic criteria (structural strength or performance) drove the determination of MGW. Sometimes you can get a hint, like with the C-172's. The original 40-flap C-172N's had a MGW of 2300 lb, but if you get the flap system limited to 30 (no other changes required), you get a 100-lb MGW increase to 2400 just like the later C-172P's. That tells you the driver in MGW was the balked landing 3.3% climb gradient test (see 14 CFR 23.77) -- by reducing flap deflection, they met the minimum gradient with another 100 lb aboard, and met all other tests either way. However, in nearly all cases, unless you have access to the manufacturer's design and test data, there is really no way to know what's driving the limit.

BTW, there are a couple of C-150 150HP conversion STC's, and one but not the other has an increase to 1700 lb in the MGW. AFAIK, the only difference is paperwork, and if you have the STC with no increase, you can buy the paperwork to kick it up to 1700 from the other STC holder. That suggests that performance, not structural strength is the driver. However, both STC's add maneuvering limits, so that may not be the case. In any event, whatever the certificated limits for your plane as it is documented are, stay within them.
 
Eamon, on a checkride the applicant is PIC. Can the DE waive that? It would be interesting how the FAA would rule in the aftermath. Shared PIC?
 
Richard said:
Eamon, on a checkride the applicant is PIC. Can the DE waive that? It would be interesting how the FAA would rule in the aftermath. Shared PIC?
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I called the owner of the FBO to check if I was being set up. The DE worked for her as her chief pilot also. I know it was wrong, but She said go for it, its ok. My CFI was 195 so every flight we took was about the same.

I would not do it now knowing what I know about how the FAA works. But as a student pilot & a jump pilot, I can tell you that a 152 & a 182 WILL handle way over gross with ease. The disclaimer is that I have seen this at sea level. I would not think of it in Denver

Are there any 152's in Denver? LOL
 
Richard said:
Eamon, on a checkride the applicant is PIC. Can the DE waive that?
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Yes.
14 CFR 61.47(b): "The examiner is not the pilot in command of the aircraft during the practical test unless the examiner agrees to act in that capacity for the flight or for a portion of the flight by prior arrangement with:
"(1) The applicant; or
"(2) A person who would otherwise act as pilot in command of the flight or for a portion of the flight."

This is used most often when it's IMC on the day of an instrument rating ride. Some examiners will do the practical test under IFR with the examiner as PIC, but not many will do this as they are treading a thin line between allowing the applicant to bust both the ride and the examiner's pilot certificate versus stopping the applicant before the parameters are exceeded, which provides the applicant grounds for an appeal of the bust.

It would be interesting how the FAA would rule in the aftermath.
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Not really -- the decision of who was PIC would be well-documented.

Shared PIC?
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No such thing.
 
Joe Williams said:
Mine told me it was fortunate he'd been dieting, because he just lost 10 pounds. Happy coincidense, so had I!! That and having precisely 12 gallons of gas on board made us legal.
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Me, 250. Instructor, 240. Full fuel (24 @ 6 ) 144. 634 pounds payload.

Cessna 152 II, MRW 1675. Measured Empty weight 1174. 501 max payload.

133 pounds over gross, hot day in MI, it flew just fine, though CG was WAY forward, made power on stalls kinda fun.

Of course I didn't know then what I know now ;-)

I switched to a Warrior II about 10 hours before my checkride when the owner of the 152 sold it (the day before my checkride).
 
Ron Levy said:
In most cases, you have no idea which of the two basic criteria (structural strength or performance) drove the determination of MGW. Sometimes you can get a hint, like with the C-172's. The original 40-flap C-172N's had a MGW of 2300 lb, but if you get the flap system limited to 30 (no other changes required), you get a 100-lb MGW increase to 2400 just like the later C-172P's. That tells you the driver in MGW was the balked landing 3.3% climb gradient test (see 14 CFR 23.77) -- by reducing flap deflection, they met the minimum gradient with another 100 lb aboard, and met all other tests either way. However, in nearly all cases, unless you have access to the manufacturer's design and test data, there is really no way to know what's driving the limit.
Click to expand...

Penn Yan Aero has an STC for the C-172N that drops an O-360 in the nose and limits the flap travel to 30 degrees. Result - a 250 pound increase in the max gross to 2550 pounds. Climbs like a homesick angel with just one on board. I can put 753 pounds in the cabin with full long range tanks, a larger load than our club's Arrow or C-182 can take with full tanks.
 
Dave Krall CFII said:
url="http://www.cessna150-152.com/transatlantic.htm"]http://www.cessna150-152.com/transatlantic.htm[/url]
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9700 miles 105 hours, in a c-150, WoW!

taking off 500 over gross. I wonder what the stall speed is at 500 over gross?
 
Eamon said:
Are there any 152's in Denver? LOL
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I've seen them in COS on occasion and we're higher than DEN by 500-800 ft give or take a bit depending on where in DEN. I watched one take off early one summer morning in front of me while it was still fairly cool with two people onboard. I don't know if they had any baggage or not but their climb rate was, shall we say, exciting. I decided right then and there you won't catch me doing that nonsense. :no: :no: :no: Then smiled evilly as I pushed the throttle in on the lightly loaded 180hp STOL CE172 and went to Vx. :goofy:


Someone said you can't pull banners with 100hp CE152. Are you sure? I use to fly a friend of mine's 152 that he pulled banners with and that definitely wasn't 150hp on the front. I think his banners were smaller and more length limited than some are though. Maybe that's how he got away with it. He did have some interesting stories to tell though like hooking a barb wire fence with the hook. BONG! :hairraise:
 
Eamon said:
300 FPM more climb
Click to expand...

An extra 50 HP ought to improve the climb of a 1600# airplane by about 1000 FPM.

50 * 33,000 /1600.
 
NC19143 said:
9700 miles 105 hours, in a c-150, WoW!

taking off 500 over gross. I wonder what the stall speed is at 500 over gross?
Click to expand...

Power off it should be (19/16)^.5 times the 1600 # stall speed (about 9% higher).
 
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