Sparrowhawk weights

[okikuma]

I'm surprised to see on the AAI website that the Sparrowhawk II empty weight is 850 lb and the gross weight listed as 1500 lb. That seems heavy to me.

Am I correct in assuming that most of the aircraft weight is because of the engine and cooling system? What is the weight of the Sparrowhawk II without the EJ25 engine and cooling system installed?

Wayne

[Brent_Brown]

What happened to the the lighter sport gyro?

[Harry_S.]

It's a BIG machine. Big machine require big components.

My RAF is about the same weight.


Cheers :)

[Mark Sanders]

Sparrow Hawks are Experimental only their to stalky to go lite sport. If you want lighter aircraft open cockpit would be better.

[gyroplanes]

Sparrow Hawks are Experimental only their to stalky to go lite sport. If you want lighter aircraft open cockpit would be better.

Actually, you can certify a SparrowHawk in ELSA (Light Sport). You just have to keep the gross weight under 1320 lbs.

This applies only until 01/31/08, 11 mos from now, after that EAB only.

[Hognose]

Jan Eggenfellner quotes 360 lb. for his 2.5 Soob FWF package for airplanes. here (http://www.eggenfellneraircraft.com/H4%20Engine.htm) It's probably about a wash with the weight of the AAI Sparrowhawk kit.

cheers

-=K=-

[rtfm]

Hi,
The engine might be a tad on the robust side of light, but so is the cabin. I once helped move a SH cabin from one side of a garage to another, and it took two grown men to pick it up and shift it. It is a real fatty.

Duncan

[Mark Sanders]

how you going to do that. please explain keeping under 1320 and still fly tandom with 23 gal fuel.

[okikuma]

Hognose, I was figuring on 350 lb for the EJ25 and cooling system.

A Lycoming O-320 weighs in at 263 lb dry with starter and altenator. Replace the starter and altenator with lighter aftermarket units and I bet an O-320 will weigh in at about 250 lb. Remove the stock carberator and replace it with an Ellison Throttle Body unit and remove the stock exhaust system for a lighter one and I bet another 10 lb could be saved.

I'm sure the RAF cockpit weighs a little less than the Sparrowhawks. I'll guess 10 lb less. A different set of lighter weight wheels and tires could probabally save another 10 lb. So, one could conceivably build a "Sparrowhawk like" two place CLT Gyroplane with an empty weight of 720 lb. Declaring a gross weight of 1320 lb would leave 600 of useful load. Not bad for a O-320 powered two placed enclosed gyroplane.

I'd like to hear some comments.

Wayne

[Aussie_Paul]

Hognose, I was figuring on 350 lb for the EJ25 and cooling system.


I'd like to hear some comments.

Wayne

Hi Wayne, I think you might be a little pessimistic re the ej-25.

In the next couple of weeks I will be able to weigh a 167 hp ej-25 SOHC with an Autoflight gearbox.

The ej-20 version with everything including exhaust, except the radiator and water was 120 kg, or 264 lbs.

The late ej-25 SOHC series engines have really improved the power to weight ratio of the Subaru instalations.

Aussie Paul. :)

[Brent_Brown]

Hognose, I was figuring on 350 lb for the EJ25 and cooling system.

A Lycoming O-320 weighs in at 263 lb dry with starter and altenator. Replace the starter and altenator with lighter aftermarket units and I bet an O-320 will weigh in at about 250 lb. Remove the stock carberator and replace it with an Ellison Throttle Body unit and remove the stock exhaust system for a lighter one and I bet another 10 lb could be saved.

Wayne


From what I can find a 0320 wet fwf or in pushers fwb is in the 325 lb range. sure you can save weight and I think the 0320 is a better option than the ej25.

[r.coplen]

Brent,

The Lycoming 320 is a very popular engine but using this engine would add at least $15,000 to the SparrowHawk price and maybe much more with the re-engineering. I have built two SparrowHawks and find that in both cases the 600 lbs usefull load is sufficent for our needs. AAI lists 850 lbs but mine came in at 810 dry weight. It is 5 lbs heavier than Randy Roger's RAF. For the price, I think it is a great choice for an enclosed gyro.

[PTKay]

Xenon, with MUCH bigger cabin is 450kg (1000lb) ready to fly
in the European Ultra Light class...

;)

[Hognose]

Oh, I forgot about this thread. Randy's comments are interesting. Also for Wayne --

1. you can't compare a FWF package (incl. mount and prop!) with a dry bare engine.

2. a too-heavy engine might mean you "get" to tote a lot of extra lead in the form of ballast. Since aircraft really, really, really benefit from being as light as possible, there's no excuse for toting weight that has no purpose but weight (to see why weight is insidious, poisoning performance three ways, read up on "Breguet's Range Equation." You'll be glad you did!)

3. It's funny you should mention the Sparrowhawk cabin. After leaving AAI/Groen, Jim Mayfield said in this forum that he wanted to make it lighter but the tooling costs were prohibitive at the time. Since then, AAI has made the cabin structure at least 30lb lighter. It's part of the Sparrowhawk II improvements and I bet Randy could tell you more. I think his gyro has the original cabin, which means that with attention to weight a 780 lb empty weight is possible. Hmmm...maybe it was his first s'hawk that that the original cabin.

4. Builders love to add bells and whistles to their aircraft. Sometimes you see things that make you pull your beard... a Kitfox with a full IFR panel of gyros and radios? WTF? Anybody that's out flying IFR in a Kitfox needs to have his head examined... one of the bells and whistles that we tend to add is too much engine. This is especially true in a gyro. Your speed is limited by drag and after about 80 HP adding more power just increases rate of climb (or altitude performance) and fuel burn. But you get less increase in ROC than you might expect for the percentage of surplus power, because in most cases the more powerful engine is much heavier (the exception being a turbo, which doesn't add much weight for the power. Instead what you trade off is reliability and durability!)

Engineering anything is a process of trading things off. If it's done right, the finished product is light and elegant (one example from the gyro world is the Dominator). Tinkering with the tradeoffs made by the plans or kit designer is risky for at least two reasons: first, the tradeoffs in the final version probably resulted from info or knowledge you don't have, and quite probably from experience in a process of iterative design. Are you sure no one at the factory had your brilliant idea before? (I personally operate on the principle that if I can think of it someone else can, too). Second, the tradeoff might appear to save something (usually money) or maybe it is just to use a favourite technology (Mazda rotary fans do this all the time). But whatever the reason, I guarantee that the redesign will hit snags and take longer than anticipated. The time is a killer as it's one resource you can't manufacture or buy. Time is the biggie, but there are two other problems as well: Your likelihood of completing and flying an aircraft decreases exponentially with each degree you depart from what was done before. And the resale value of your aircraft tends to decrease with departures from the norm (the exception is if your departures are so high quality that you get a bunch of magazine cover stories. But in that case, you paid the price in time... and you will pay it in time again, because the value may have gone up to "the right buyer" but the number of right buyers went down with each personalization you did, so your machine will be much longer on the market if you want to earn that price.

There are exceptions, of course. There are people who can improve a design, or make one from a clean sheet. But with dozens of gyro makers chasing mere dozens of customers, you're not going to make your R&D back any time soon.

cheers

-=K=-

[Hognose]

This .pdf file may be of interest. It contains bare and dressed weights for a number of common aero engines.

It includes weights of Hirth, Rotax, Verner, and Continental and Lycosaurus, including both current and some legacy motors. I thought I had Franklin and PZL-Franklin motors in here but I do not. The certified engines are reported in considerable detail, as the weight difference between letter-suffix versions can be substantial. (Warning: if you have a version that is not in this table exactly, this table is only going to be a very ballpark estimate of its weight).

The information came from the manufacturers themselves (either websites or printed propaganda), or from the Sky Ranch Engineering Manual, in the case of most of the certified motors. Both bare and dressed weight are reported, if known. (A zero doesn't mean the engine is weightless, it means I had no data). Dressed means with accessories as specified (starter, mags, exhaust) but no mount or prop. Those, as they say, will cost ya extra.

[dragonflyerthom]

great post and true Kevin

[Heather Poe]

AAI has made the cabin structure at least 30lb lighter. It's part of the Sparrowhawk II improvements and I bet Randy could tell you more. I think his gyro has the original cabin...
It does have the original cabin.
a 780 lb empty weight is possible.
It also has the original smaller and lighter 2.2 liter engine.

[r.coplen]

In the end it comes down to cost. As PTKay said I can get a larger, lighter machine but it will cost me close to $80,000 by the time I get it delivered and added the options similar to what I would want on my SparrowHawk. To be fair, my options, delivery and sales tax run my price up to $49,000 on the SparrowHawk and I still would spend 150 to 200 hours making it. But that is the trade off to save about $30,000. I still have a great ride and David Overman, our CFI, has given a lot of people training in my SparrowHawk and will continue to do so.

[dragonflyerthom]

And American gyro pilots are cheap. I would rather do the work myself. I know I was trying to get back into the air with a rotorcraft as cheap as comfort would allow.

[okikuma]

Aussie Paul,

Have you weighed your EJ25 yet? I'm so curious to know to compare.

To keep the discussion going .....

The following certified engines weights I found listed in the book titled: ENGINES FOR HOMEBUILT AIRCRAFT & ULTRALIGHTS by Joe Christy.

Continental:
A50, A65, A75, A80 ......170 lb.
C75, C85, C90 ...... 158 to168 lb.
O-200 ...... 218 lb
O-240-A ...... 246 lb
C125 - C145 ...... (weight was not given, can't be more than O-300)
O-300 ...... 268 lb (without starter, generator & oil cooler)
IO-346-A ...... 297 lb

Lycoming:
O-235 ...... 240 lb.
O-290 ...... 236 lb.
O-320 ...... 268 lb.
O-360 ...... 282 to 290 lb.
IO-360 ...... 296 to 332 lb.
TIO-360 ......386 lb.

The weights Christy gives are listed as "dry weight" (without oil). He doesn't mention baffling or exhaust systems so it's safe to say those are not included in the dry weight. Some engine weights do include starters, generators, & oil coolers if applicable. Personally, I believe these weights given above are the most accurate because these weights are the "heaviest" I've read in print anywhere.

[Aussie_Paul]

Aussie Paul,

Have you weighed your EJ25 yet? I'm so curious to know to compare.



No not yet. I spoke to the guy Sunday eveing and all he has to do is calibrate the digital display weighing device which he hopes to get done this week. By that time we will have another ej-25 mated to an Autoflight gearbox ready for weighing.

Aussie Paul. :)