Fuse length

[why2cay]

I have a set of Sagitta 900 Wings, and i now have a fuse for them. my question is that on my stock sagitta,the fuse is 48" long, and the fuse i have is 52" long. Will the fuse length be a problem for these wings?

Thanks
Steve

[Ollie]

Don't worry about a fuselage is 4" longer. Keep the tail light because it is important.

[woro]

Longer fuse can't be a problem, in general it can help you if you have problems with stability. The only thing that can happen is that it can get tail heavy easily if only the tailboom is longer-but 4" isn't enough to cause any problems. If it's 10% longer in all directions, it can't be a problem so you don't have to worry about that. Nice flying with your Sagitta!

[schrederman]

Actually, the longer tail moment seems to differentiate between models of now and models of the Sagitta's vintage. The longer moment will smooth out the flying and allow you to use a slightly smaller tail with the same result, or the same tail with better stablilty. I remember a conversation with Cecil Haga about the Legionair sailplanes. He said if he had to do it again, the moments, nose and tail, would be longer and the tail surfaces smaller, and airfoiled.

Jack Womack

[BMatthews]

I've got a model that has two fuselages for the same wing and stab. One is pure glider and the other electric. The electric has a slightly longer tail and smaller fin and rudder. The longer tail with smaller fin and rudder is a FAR better flyer than the short fuselage glider.

As mentioned just watch out for the tail weight issue. Build it light but strong.

[histarter]

Actually, the longer tail moment seems to differentiate between models of now and models of the Sagitta's vintage. The longer moment will smooth out the flying and allow you to use a slightly smaller tail with the same result, or the same tail with better stablilty. I remember a conversation with Cecil Haga about the Legionair sailplanes. He said if he had to do it again, the moments, nose and tail, would be longer and the tail surfaces smaller, and airfoiled.

Jack Womack
Hi Jack,
Interestingly I mixed Cecil's and Walter Pankin's (Rainbow fame) philosophy together after flying Cecil's Chaparral. Tempering that design, with Don Chancey and Dave Thornberg's flying style, I came up with short coupling technology (with high damping rates using airfoils for tail surfaces) that I found was very successful for performing aggressive duration in the lower air. NOTE: My evaluations were conducted against the probability of making a predetermined task; rather then gazing at the sporadic results of staying up for undisciplined time periods (in the upper air where performance becomes more crucial). ;)

Since concentration currently is for soaring in the upper air, that more resembles slope conditions, I am planing the construction of a new 100 inch wing for my 2 mtr Shuttle (clone) that incorporates a flying wing profile on my parallel chord design, to cumulatively assist the tail surfaces for stability. Tail surface then becomes a controlled upset (Alpha program limited) defining the stable limits of a fixed speed range - meaning full down trim is as fast as I wish to go (just not open ended) and full up trim the center for slow flight - with short coupling controlling the time constants for corrections. ;)

This different approach should be effective for me to play with the upper air, after I get my prosthesis to enable me to walk again, that now looks promising. A 3 mtr wing is a bit much for the ballasting system used for my Shuttle, and my ability to launch. Because of the CL limitations imposed by a reflexed profile (meaning more zip for the mass) I can visualize my personal advantage working the upper air, and it will be interesting to compare this philosophy against 'normality'. :rolleyes:

This project is for my personal interest/curiosity since I realize I am over the hill when it comes to competition (something I am not striving for) so if I use spoilers, they will opening downward for a softer, steep but slow landing. :D

[schrederman]

Hey Al,

Actually the full-scale Genesis II ws just such an animal as you describe. It is a flying wing that has a fixed trailing edge except for the ailerons... no they're not elevons. Just aft of the trailing edge, there is a very tall, raked fin with a slender rudder, At the top of that is a full flying elevator... not a stabilator, as the wing's reflex actually handles the stabilizing task. Unless providing pitching force, the elevator has no other effect on the flight of the aircraft. At speeds of 100 kts and above it is decidedly better than a Discus. Unforthunately, at speeds lower than that high cruise, the majority of standard class sailplanes seem to have the advantage... hence the Genesis never really "took off," if you'll pardon the pun. Just about everyone I've heard comment on this ship says it doesn't handle well, but since I have no personal experience flying it, I can't comment there. If it is a bear while sitting on the CG, I can only imagine trying to fly it well while standing on the ground. The newer full-scale stuff is kind of following our modelling trend... with longer relative tail moments and smaller, optimized tail surfaces... :eek:

Good luck with your project... Will we see you at TNT this October?

Jack

[histarter]

Hey Al,

Actually the full-scale Genesis II ws just such an animal as you describe. It is a flying wing that has a fixed trailing edge except for the ailerons... no they're not elevons. Just aft of the trailing edge, there is a very tall, raked fin with a slender rudder, At the top of that is a full flying elevator... not a stabilator, as the wing's reflex actually handles the stabilizing task. Unless providing pitching force, the elevator has no other effect on the flight of the aircraft. At speeds of 100 kts and above it is decidedly better than a Discus. Unforthunately, at speeds lower than that high cruise, the majority of standard class sailplanes seem to have the advantage... hence the Genesis never really "took off," if you'll pardon the pun. Just about everyone I've heard comment on this ship says it doesn't handle well, but since I have no personal experience flying it, I can't comment there. If it is a bear while sitting on the CG, I can only imagine trying to fly it well while standing on the ground. The newer full-scale stuff is kind of following our modelling trend... with longer relative tail moments and smaller, optimized tail surfaces... :eek:

Good luck with your project... Will we see you at TNT this October?

Jack
Well Jack, you are actually describing the effects that I am looking for. I started a Woogar project wing about 4 years ago, when I was still going out flying statistics. My crippling got worse, and from then on I was flying Shuttles and electric at Pilot Point – forced to use my winch instead of my walk-a-thon histart. Things have gone downhill, and I gave away lots of equipment, other than my 2 Shuttles and Oly III (the last machines I was still able to physically handle). Surviving one small heart attack, and discovering booze can relieve heart disease, I seem to be coming back. This week I had a 500% improvement in my workout, without suffering any consequences! Rx is at 1 qt imported whisky per week!! :o

Doing research on the Blackbird controls (and application of the bottom spoiler), I believe the in-between machine situation has merit. First you have to clean your mind of your current prospective. ;)
We are talking low AR here, and low alpha. At CL 0.6 I am seeking a loading that will give me about 20 mph for the low speed end of range, and 45 mph for the upper end. Because of the limited low CL, the range in ballast for shifting higher in airspeed would be much less, and within the range of the 2mtr version. Now if successful at standard, the 3 mtr version at 1440 square should be pretty effective, by size alone (with my cataracts removed i.e. visible a mile away). :D

At least it gives me goals to work for, and a reason to clean up my shop for the new project - that is designed to humor myself (without concern for TNTs), though I may bring her out for an occasional launch (regardless of any future altitude restrictions)..LOL :eek: :eek:

[schrederman]

Well,

I drink imported whiskey, too... Gentleman Jack is imported from Lynchburg... right? Remember, if I'd taken Delores' name, I'd be Jack Daniels...

Jack

[histarter]

Well,

I drink imported whiskey, too... Gentleman Jack is imported from Lynchburg... right? Remember, if I'd taken Delores' name, I'd be Jack Daniels...

Jack
Another thought on Genesis II, that I learned from my Woogar project; is that the tailplane adjusting an alpha increase by forcing the reflexed surface to greater CL, needed more lift (so I used an inverted profile) - whereas forcing reduced alpha was like power steering (adverse pitch enhancement). ;)

If you get a chance to play with Genesis, you might consider turbulating the stab's underside 12% and 33% with 70 mil thick trips to engage lift bias to compensate an unruly force. The amount of drag increased by this experiment should equal a gaggle of flyspecks!! LOL :D

Just remember, concern is for low speed improvement, and a good aerodynamicist could carry the equation to perfection, and "proper" balance. :confused: