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Old 09-11-2017, 02:28 AM   #1
Dennis5678
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Default Acro Sport II as LSA

I know what your thinking. Can't be done!
Well Jack made his Acro Duster II LSA
So what does a builder have to do what Jack did to make an Acro Sport II
a LSA.
I know the requirements for LSA so let's start with the engine.


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Old 09-11-2017, 03:04 AM   #2
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Who has built one with a O-235? Cub might out climb you. Weight is the real killer to get the stall down. Jack's plane as LSA is really a single seater. Every detail has to be evaluated. Smizo's build but make everything about weight. How light can you make wing tips, and deck, sheet metals, wing walk. If you can make it light, can you just get rid of it? No electrical and electronics, lightest paint job you can put on despite looks, grade weight and thickness of raw materials. The big thing is to back up from 1320. How much people and how much fuel will give you a target where the empty weight needs to be. How close is OK? Loose another 50 lbs would be good.


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Old 09-11-2017, 03:30 AM   #3
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I would think that Smizos airplane would qualify if the gross weight were listed at 1320 or whatever the legal LSA weight is. At that weight the stall will be lower than the 2 place gross weight stall.
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Old 09-11-2017, 11:04 AM   #4
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Start here:
  • Crew: one
  • Capacity: one passenger
  • Length: 18 ft 10.25 in (5.7468 m)
  • Wingspan: 21 ft 8 in (6.60 m)
  • Height: 6 ft 7.75 in (2.0257 m)
  • Wing area: 152 sq ft (14.1 m2)
  • Empty weight: 875 lb (397 kg)
  • Gross weight: 1,520 lb (689 kg)
  • Powerplant: 1 Lycoming O-360 4-cylinder, air-cooled, horizontally-opposed piston aircraft engine, 180 hp (130 kW)
  • Maximum speed: 152 mph (245 km/h; 132 kn)
  • Cruise speed: 123 mph (198 km/h; 107 kn)
  • Stall speed: 53 mph (85 km/h; 46 kn)
  • Range: 430 mi (374 nmi; 692 km)
  • Service ceiling: 20,000 ft (6,100 m)
  • Rate of climb: 1,200 ft/min (6.1 m/s)
  • Wing loading: 10.0 lb/sq ft (49 kg/m2)
I've been told in two different forums, Tailwind and Pitts Special, that at 1320# one needs 130 sq. ft. wing area to meet the LSA 51 mph stall speed. In both cases a light sport compliant airplane becomes an oxymoron, they would no longer be a "Tailwind" or "Pitts Special".

In the case of the Acrosport 2 it should be easy, I suspect that at 1320# the stall speed would be compliant? (My Acroduster 2 with 130 sq. ft. wing area also just meets the required stall speed at 1320#)

The problem is useful load. Getting the empty weight down in order for the aircraft to remain a viable TOO PLACE aircraft is problematic.

Just do the math.

If you look at most aircraft purpose designed as Light sport the empty weight will very likely be under 800#?(I haven't actually looked) But based on my experience with the Tu-holer it must be the case. My Tu-holer easily meets the stall speed @ 1320# (48 mph) but with an empty weight of 837# it's useful load id just barely "useful" with my fat 200# . Marcia is still her trim self and with 20 gal. of gas the total weight is 1313# (you can do the math)

My Acroduster 2 weighs 912#. It is NOT a viable 2-place airplane. I recall running the numbers and if I leave the chutes behind, fill with min, oil, Marcia and I could add about 6 gal. of gas and remain under 1320#. We aren't going too far with less than an hours fuel. Indeed I would hesitate to take off with only 6 gal. although I suspect with it's integral header tank the AD2 would run down to 1 gal. or less?


Back to the Acrosport 2. I think Tom and Neil nailed it. At 1320# I suspect the stall would be compliant. The other consideration is cruise speed which can be limited by propeller or placard, if necessary.

Based on published data above it would seem to be relatively easy. 875# is the claimed empty weight of the Acrosport 2. I wonder if they weighed it before they covered it?


Oh, remember that you will probably need to build from scratch or aquire a project. Once an aircraft is licensed/registered at a higher gross weight you can't make it lighter to be LSA compliant. I may have the only LSA compliant tu-holer and AD2?

Jack
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Old 09-12-2017, 02:34 AM   #5
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Quote:
Originally Posted by EAABipe40FF View Post
Start here:[LIST]

My Acroduster 2 weighs 912#. It is NOT a viable 2-place airplane. I recall running the numbers and if I leave the chutes behind, fill with min, oil, Marcia and I could add about 6 gal. of gas and remain under 1320#. We aren't going too far with less than an hours fuel. Indeed I would hesitate to take off with only 6 gal. although I suspect with it's integral header tank the AD2 would run down to 1 gal. or less?

Jack
Aren't the Carbon Cubs about 912 lbs?
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Old 09-11-2017, 11:33 AM   #6
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My airplane would make it. I still listed gross as 1550, but could have done 1320. the airplane, me, full gas and full smoke come in at 1350. however that doesn't leave any room for the most important part of an acrosport 2 in most peoples opinions..... the second person. i don't see any way i could have made my airplane any lighter (with how it is equipped) other than very light paint work instead of the fancy one i did.
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Old 09-11-2017, 12:35 PM   #7
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Once again the demise of a good design, the second seat.
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Old 09-11-2017, 12:48 PM   #8
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875lbs is not doable for a two place Acrosport 2 in my opinion. My old AcroSport 2 was built to Plans for the sake of argument. And had a very light fabric job on it. No inverted oil or fuel. Handheld radio. No transponder. And weighed 1016lb (I think that was it. ) The only weight savings could have come from the use of a earthx over the Concorde. I believe it already had the light starter. So maybe a realistic 950lb. Maybe. But let's say you are magic and get one down to 900lbs. Now add 12 of gas. (One hour plus 30min reserve) 72lbs. Now let's add two "average people" of 170lbs each. (Try finding two of those folks! I blame the cattle industry and all the steroids in our food! ;-) you're there weight wise but mine still stalled at 60 indicated with only me in it. For arguements sake i guess it can be done. In the real world...my guess is you would constantly be over the 1320lbs with two people. The airplane would continue to not care. But you'd be out of the regulation. With basic med...I think the whole LSA thing looses its draw.
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Old 09-11-2017, 12:53 PM   #9
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I think the published 875 figure was when the EAA weighed the airplane before it was finished. Things like cover and paint, systems etc. weren't in the original weighing. Looked good in the brochure but wasn't realistic.
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Old 09-11-2017, 02:13 PM   #10
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The ten year since last third class will keep some at LSA over basic med.
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Old 09-11-2017, 02:36 PM   #11
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I figured that 875#'s was bogus. I once saw a sheet listing finished AS2's and most were over 1000#'s with several a few lbs. under but none close to 900.

Oh well
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Old 09-11-2017, 02:56 PM   #12
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The AS II is still a fine choice at a reasonable empty weight. Since basic med was mentioned, I'm glad there is still a sport pilot choice. Basic med got watered down and excludes anybody with heart surgery even though many of these people are in better shape than some people that do qualify for basic med. Got a friend who got excited about all this, now he is glad he can still fly his Pietenpol. Basic med is only good for some.
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Old 09-11-2017, 03:14 PM   #13
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I think you could do 875. Mine is 1030 with oil, a heavy engine and metal prop, .032 tins and full controls in the front. Stall is 55.
Narrow deck O-320, Catto prop, fabric fuselage sides, no starter or boost pump, carbon control pushrods.
Stall speed would come down that last two mph or maybe I might have to test fly it more carefully.
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Old 09-11-2017, 07:23 PM   #14
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I do wonder about the stall speed we see on most homebuilts. The biggies spend a lot of dollars to get an accurate stall speed.
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Old 09-11-2017, 07:36 PM   #15
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Haven't seen a fed at any airports with a radar gun. Kind up to the test pilot and what is determined during phase 1 testing and what is entered into the operating limitations. Obviously you aren't going to squeak a Lancair IV in to meet LSA criteria but otherwise they all fly like Legal Eagles if you ask me.
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Old 09-11-2017, 09:05 PM   #16
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The AS II as an LSA is going to carry around a lot of extra weight in it's structure that it doesn't need as it's a 1550 lb aeroplane. Why not start with the AS I which is a 1350 lb aeroplane and stretch it to add another seat?

These sorts of aeroplanes without Rotaxes and minimal structure (like Tecnams and the like) need to have other compromises made to fit in the LSA class. The obvious one is not to have duals and only one set of instruments.

I have wondered that it would be less engineering and lighter weight to fatten an AS I to seat the 2nd person side-by-side, and slightly staggered. It's just a jump seat, not something for a 3 hour cross country. No dual controls. You could even have two different cockpit combings, one for two occupants and one for one occupant.

To take a set of AS II drawings and sit down and build an LSA compliant plane is a big ask and probably a bit of a risk. Like the LSA Pitts thread, the final answer is; Push away the keyboard and get cutting metal.

Andrew.
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Old 09-11-2017, 10:30 PM   #17
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I have been helping a friend get his Hatz lightened up. He bought a de-registered wreck and started over. It will be sans any front pedals and instruments but will have a stick. We cut a lot of heavy stand offs and other brackets and went back lighter. It will have a C90 with a light weight starter with a batt. and no charging system. Rick Hansen who has built several Hatz's has done the same thing, documented on youtube. The second seat sure makes extra work.
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Old 09-12-2017, 12:17 AM   #18
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I only mentioned that Smizos airplane would be compliant because it was built as a single seat aircraft. An Acro II built as a two place aircraft would never make it as LSA compliant.

I did have a conversation with my DAR buddy as to whether or not their could be such a thing as being LSA compliant when configured as a single seater but remain convertible to a two seat aircraft by installing the forward controls, windshield two place sheet metal and seat and flown as EAB. There is no clear way to do this.
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Old 09-12-2017, 01:38 AM   #19
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Neil I bet builders said the same thing about the ADII but
Jack did it. I should put my money where my mouth is on this
subject and just shut up about it.
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Old 09-12-2017, 03:09 AM   #20
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I think LSA Carbon Cubs carry 25 gal of fuel where the non LSA carry 50 gal. I think the X-Cub empty is more than LSA gross, so they make things all over the map.
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Old 09-12-2017, 05:05 AM   #21
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They say 892# depending on equipment. Same equation, with two adults not much room for gas. But for little guys and gals the useful load might be plenty.

I imagine they simply "are creative" when it comes to fuel load since the same basic airframe is safely flown at much higher weights? Of coarse I could do the same thing........NOT.

Of coarse for many a 912# EW is viable if you only carry a passenger for local flights which is how I fly my airplanes for the most part. I was able to take my pastor for a short ride in the Spezio today, He's a small guy and 10 gal. was more than enough.

Jack
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Old 09-12-2017, 10:57 PM   #22
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Jack,
Did he reach out and touch the face of GOD
Us Avaitors know this all to well. Taking up a Pastor, Preacher or Father up to see
what we see is enlightening to both.
He sure looks happy.
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Old 09-12-2017, 11:09 PM   #23
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He's a former 82th Airborne chaplain, I'm just glad the chute doesn't fit in the front pit.
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Old 09-14-2017, 12:13 AM   #24
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If you are building the plane, you are the manufacturer.

There is a One Design that is LSA, it's one of the members in my IAC chapter.

Legend Cubs with 180hp had placards limiting RPM in cruise to meet LSA requirements.

Where there is a will, there is a way.
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Old 09-14-2017, 01:31 AM   #25
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I have the plans to the Acro Sport II
I see that it is over built and heavy. If you change some things with the help of an Aeronautical Engineer you could take weight off. Then you don't have an Acro Sport II
anymore. So you call her what you want and set your own LSA permitters
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