5 January 2024
So, elevator tilted right can be substituted to down on elevator left side and up on elevator right side.
See lunchbox or wurfgleiter:
They are the same design without elevator tilt or gurney flaps: 8"*3"*1/8" wing, 1/32" tail, 1/2"*1/8" fuselage.
Using thumb against ring finger and index and middle finger.
Maybe I shall do two. One with 1/8" wing and one with 1/16" wing.
From Outerzone, there is one design which separate nose from the rest of the fuselage.
The nose is glued under the other fuselage piece.
Maybe by using double-side tape can prevent the damage to fuselage on vertical crashes?
Also there is one design for flapped wing. After the wing dihedral is set, the rear 40% is slotted so that it may be bent downwards to create an undercambered airfoil.
4 January 2024
I think, and maybe this is wrong, but the reason for not being successful in HLG in my youth is because the transition to glide was too difficult to obtain consistently. And this could be because I chose the design of Slarmi. Now, if I had chosen a HLG design with more dihedral, the transition could be changed to a roll transition and this would have more consistent transition recovery.
Another possibility for failing is that I used left rudder for the left glide. This is a dangerous setup because it may lead to spiral dives, and soon the fuselage would break, subsequent gluing doesn't help much, soon I get frustrated and lost interest.
Now a new chuck glider or HLG:
- should be large enough both in span and tail moment;
- make it light and strong, not heavy and weak; it depends on whether more penetration is required or is unnecessary and this depends on the wind condition; choose light over heavy;
- the wing should have sufficient dihedral with a bit of wash-in on the left tip (being a right hander);
- the elevator piece should be tilted to induce left glide (tilted elevator does not affect the power launch phase).
Adjustments:
Decalage is commonly stated as zero-zero for maximum launch height but yet remain stable because of CG placement, the lifting properties and long tail moment. The CG will determine the stability to recover, offer some recovery property but not excessive as it creates drag.
Use a little plasticine to trim the CG during trimming. The little plasticine will not be sufficient nose weight, make the nose stronger (equals heavier). Plasticine is oily clay, if the surface is porous, the oil will soak in, so do well by making the nose stronger, and make it impervious by either using non-porous material such as plastic or aluminium or by sealing the wood surface where the plasticine is to stick.
The fin will be perpendicular to the wing, the elevator will be tilted; glue the fin on the opposite edge to the seating of the elevator, set it straight without any turn.
Use double-sided tape to temporarily set the tilt of the elevator; this allows tilt adjustment and even incidence adjustment.
Trimming:
- Check the CG's left-right placement; if left wing is heavier than the right wing, it is possible to add minute amount of weight to the right wing tip to balance the wing, but if it is the right wing is heavier than the left, leave it be for the moment until final trimming.
- Start by hand launching a basic glide so that the CG fore-aft placement is not too far off. No need to put in unnecessary effort as it cannot be accurate, but check if fin is sized too big.
- Add short 1/2"x1/16" triangular sticks to the left wing tip, at both sides of the tip dihedral joint, this will introduce some wash-in which helps to keep the left wing up during a left glide. With this type of wash-in, the chucky shouldn't roll right immediately and it will also introduce some drag on the left wing, causing the model to turn left.
- Observe the left glide path if it is better to shift the CG or necessary to adjust the elevator tilt. The glide will be yawing, i.e., the fin is not in line with direction of glide, it is possible to trim the fin left for tighter turn, do not use too much fin trim, the limit is when the fin is inline with the direction of glide. In general, fin bending is some sort of a drastic solution as it will affect the power launch phase as well.
- When the basic glide is stable, set the tail tilt solid.
- Progress to power launch and check the recovery transition. By this stage, there is nothing much to do except to modify how the glider is launch.
- Possible trimming is the minute amount of plasticine, the lengthening/shortening of gurney flaps, the elevator and then the fin.
So the general design parameters:
- Wing: 14" span (because I think that's my speed limit now), 4" root chord, straight trailing edge with quadrant tips. Equal polyhedral at 4"; 1" rise to each 4" panel.
- Elevator: 6-8" span, 3" Rc, 1" Tc (15-20% wing area)
- Fin: 2" span, 2" Rc, 1" Tc
- Underfin: 1" span, 3" Rc, 1"Tc
- Fuselage length of 22" (1.5c+1c+3c moment).
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