Quantcast

Starduster Too 220 cont - high sink rate

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

Dana

Super Moderator
Staff member
Joined
Apr 3, 2007
Messages
9,530
Location
CT, USA
100 mph sounds high, though I have no experience with this aircraft. Is it the one with a Kinner engine formerly from Connecticut?

But a radial will be more draggy, so you'd have to come in with some power or steeper... but if you come in without power you'd need enough excess speed to carry you through the flare. Kind of like an ultralight...

-Dana

I have a hard time deciphering the fine line between boredom and hunger.
 

Toobuilder

Well-Known Member
HBA Supporter
Log Member
Joined
Jan 19, 2010
Messages
5,016
Location
Mojave, Ca
What is the empty weight? The prototype was 1000 pounds, but these things have been built in every possible configuration over the years and the radial powered examples are often very heavy. I heard of one that was powered by an iron block chevy out of a sprint car. The FWF weight was something like 750 pounds IIRC. It flew, but was a real handful, similar to the description above.
 

djschwartz

Well-Known Member
Joined
Jun 21, 2008
Messages
982
Location
Portland, Oregon
I flew a 220 powered Starduster Too many years ago. The speed on final sounds a bit high, but not much. The airplane was very heavy; though, I don't remember the actual numbers. I believe it was easily several hundred pounds more than the design empty weight. The engine does not fit the airplane well and it is impossible to cowl properly; so, the drag is also very high. The combination of the two did result in an impressive sink rate on final so approaches were almost always power on. Visibility forward was bad even by antique biplane standards. That probably accounts for the high approach speed even more than stall speed.
 

djschwartz

Well-Known Member
Joined
Jun 21, 2008
Messages
982
Location
Portland, Oregon
The Starduster Too was designed for a 180 HP Lycoming engine with a fixed pitch propeller. Many, if not most got built with a larger power plant. But for comparison's sake, here are some numbers for that engine installation and a Continental W670 (220 HP) radial. These are only approximate numbers but the difference is significant to say the least.

Lycoming O-360

Dry weight: 290 lbs
6 qts oil: 9 lbs
Prop, fixed pitch metal: 30 lbs
Starter: 15 lbs
Alternator: 10 lbs

Total so far: 354 Lbs

Continental W670

Dry weight: 460 lbs
5 gal oil: 30 lbs
Prop, 2B20 C/S: 110 lbs
Starter: 20 lbs
Generator: 24 lbs

Total so far: 644 Lbs

So you can see that there's no way a 220 continental powered Too can be less than about two hundred pounds heavier than the original design weight even if it used a wood prop. With the more typical C/S prop it will be on the order of three hundred or more pounds heavier. Even a Lycoming O-540 installation with a C/S prop is likely to be over 100 lbs lighter than the all up installed weight of the W670. And I still haven't accounted for any other differences that the heavier engine would bring to the aircraft.
 

bmcj

Well-Known Member
HBA Supporter
Joined
Apr 10, 2007
Messages
13,597
Location
Fresno, California
Most of the radial Starduster pilots I've spoken to like to make their approach at around 85 mph (some say as low as 80), so yes, 100 seems a bit high. I know that the weight and balance issues have plagued many who have put radials in their 'Dusters, but I have heard about the balance going both ways, noseheavy and tailheavy, so the bottom line is to double check and make sure that the CG is in the proper range. I might suspect that his is noseheavy.

Stabilizer incidence is also something to consider. Often, the incidence adjustment can make a big difference in trim speed and the way the plane flies (most Stardusters have a ground adjustable stab incidence). Check too that he is getting full elevator travel. I've heard of occasions where the elevator pushrod becomes blocked from full aft travel, depending on how the stab is placed.

A radial Duster in Georgia? Is this perhaps the beatiful red and black one owned by Kevin S?

Bruce :)
 

Toobuilder

Well-Known Member
HBA Supporter
Log Member
Joined
Jan 19, 2010
Messages
5,016
Location
Mojave, Ca
...Asked him if it weighs much more than comparable and he says no...
...But what IS the weight (and CG)? You are certainly going to review the W&B figures before you fly, right? If a brand new airplane flies "funny", W&B review is near the top of the list before further flight.
 

TFF

Well-Known Member
Joined
Apr 28, 2010
Messages
13,983
Location
Memphis, TN
It also has a bigger prop windmilling out there with the power pulled back than a standard opposed cyl engine.
 

Dan Thomas

Well-Known Member
Joined
Sep 17, 2008
Messages
5,608
I would check the wing incidences. If there was wing-heaviness they were off some and were corrected, but perhaps both upper wings or both lowers are at the wrong angle and not contributing adequately to the lift. That makes one set work too hard.

Dan
 

bmcj

Well-Known Member
HBA Supporter
Joined
Apr 10, 2007
Messages
13,597
Location
Fresno, California
Look at the wing structure and covering too. Look for any angular breaks or heavy spanwise fabric seams/overlaps (even heavily masked spanwise paint stripes) on the upper surface of the wings that might trip the smooth airflow and reduce the lift or increase the stall speed. I remember a cropdusting Stearman years ago that had a heavy wing and raised stall that was finally tracked down to a fabric seam (from a repair) that fell in just the right place to affect the airflow over the wing.
 

Dan Thomas

Well-Known Member
Joined
Sep 17, 2008
Messages
5,608
Look at the wing structure and covering too. Look for any angular breaks or heavy spanwise fabric seams/overlaps (even heavily masked spanwise paint stripes) on the upper surface of the wings that might trip the smooth airflow and reduce the lift or increase the stall speed. I remember a cropdusting Stearman years ago that had a heavy wing and raised stall that was finally tracked down to a fabric seam (from a repair) that fell in just the right place to affect the airflow over the wing.
Good point. In flight, get a look at the fabric on the top of the bottom wing; see how much it's pulling upward between the ribs. It shouldn't come up much more than level with the top of the ribs. If the fabric hasn't been shrunken as far as it's supposed to, it isn't tight enough and will rise too far, disrupting spanwise flow and affecting lift.

Dan
 
Top