S8 FAI R/C Rocket Gliders

Back to Many Photos
S8 Gliders
Back to Main WSMC CD

Assembly of Stingray 3.6
S8E model in July 2000.

Stingray 3 kit bought from Nick Rivieccio. Design used Stingray 6 type fuselage, tail attachment, and nose pod

Also used extended wingtips as earlier Stingray 4.6 model did

P7170042.JPG

P7170046.JPG

P7170048.JPG

P7180052.JPG

Installation of CS-21BB servos in wing bays. Balsa glued to servo gives clearance for output arm and allows CA to be wicked-in to secure servo once laid in place against the upper wing skin. Note upside down views which show the bottom of the wing Servos glued into placed before covering with balsa Balsa "patch" glued into place over left wing bay

P7180053.JPG

P7180057.JPG

P7190058.JPG
StingRay%20Wiring.GIF

Masking tape along outer edges of balsa to prevent sanding too deep when sanding balsa flush. Fiberglassing the center section. Allowing to cure before trimming the edges and sanding the glassed area of the LE. Minimal 4-wire arrangement going thru boom. See drawing. This wiring saves mass, as well as space inside boom.

P7170044.JPG

P7170050.JPG

P7230001.JPG

P7230002.JPG

P7230003.JPG

Tail assembly. Pushrods not yet connected. Fiberglass reinforcement on bases of control horns not yet cured or trimmed. Completed tail. Plastic tubng and CA was CAREFULLY used to connect "Z" bend music wire to pushrods Completed model, with extendedtips (red).
Bagged slightly larger tail was provided by Ben Roberto, as well as nose pod and foam cores for the tips

StingRay-3.6.JPG Next:
Cuda-Flap models

for S8-P event

at 2001 flyoffs

Radically different layout than a true Cuda. Essentially used the wing core and skins from a Cuda and replaced everything else in the kit with either lighter parts or different layout (such as fuselage pod under wing).

Wing designed for a 1 x 14" flap, deploying down 90 degrees. Wing was reinforced to make up for the structural loss of the cut-out.

Cuda-X.jpg First Cuda model was completed in late April. But a dumb mistake caused it to crash on the first flight (Transmitter off).
Other than some limited hand launches the previous day, nothing was learned from the model regarding whether the flap was worth doing.

Assembly of fuselage pod. Engine is located so that the nozzle is about 1/4" ahead of the flap when the flap is deployed 90 degrees.
P7160002.JPG
P7160004.JPG
P7160008.JPG

Wing skins took a lot of time to mark out where to place fiberglass reinforcement and graphite strip. 3/4 oz glass cloth used, nothing heavier. Rather than the regular kit fiberglass tape for the TE, 3/4 oz glass cloth was applied to both sides of the TE, for the last 1/2" (orange area).
Glass cloth was applied to the TE across a 1.5" chord for the first 8" span out from the root. This was to reinforce the last 1/2" of the main wing and to stiffen the flap against warpage.

P1010010.JPG
P1010013.JPG 1/4" wide gap was cut out from the wing core, along the flap hinge line. Gap was filled with 1/4" thick balsa cut and sanded to shape to match the upper angle of the core airfoil. Balsa was glued to the core using foam-friendly CA.
When the wings were ready for skinning, red dye was used in the epoxy, looks pink when thin. Darker areas show where glass was applied. A strip of fiberglass was also added to the top and bottom of the balsa insert piece in the wing core, to further reinforce that area

CudaLayup.jpg

Core ready and Skins marked out Note balsa insert glued to core along flap hingeline

V-tail servos wired up for mounting side by side, flap servo by itself under wing just in front of engine.

Wiring was done along similar lines as the Stingray wiring shown before. However not done to the extreme it could have been, the flap servo could have shared the same bus wires as the V-tail servos

P4260001.JPG

P7290034.JPG

P4270030.JPG
P7280017.JPG

Fuselage with Flap servo pushrod exit visible Flap down on Cuda-Flap#1
Flap up on Cuda-Flap#2

A second Cuda-flap model was completed to fly at NARAM. It worked out very well, the flap a great way to do S8-P.
A third model was built to use at the flyoffs, the second one as a back-up.

P7280010.JPG

P7280012.JPG

P7280015.JPG

P7280016.JPG

Also made use of 150 mAh Nimh batteries, which are the same size and almost same mass as 50 mAh nicads. Great way to go, and 3rd servo made 50 mAh too iffy. Warning though, some Nimh packs under-perform. One pack tested to only around 70 mAh, good ones tested to around 130. The pack that tested to 70 not used for anything but ground tests. Sirius tester highly recommended. 1/8" balsa tail was glued to the TOP of the boom. Solved alignment problems and a very strong way to attach a tail on a model that by its nature will suffer rough landings.

Hitec 555 receiver has antenna over 36" long. Last 36" replaced by .015" music wire, allowed to extend out the back of the boom. Same solution as used for 35 mHz woes in Slovakia. .015" wire antenna proven out by Alex Seltsikas years before..

Cuda Flap models 2 and 3 weighed in at around 194-196 grams glide mass, with 555 decased receiver, 17 gram 150 mAh NIMH battery pack, and of course a 3rd CS-21bb servo.
My lightest Stingray-6 was 183 grams I think, with Futaba Rx, so not bad. Just not nearly as aerodynamic as a Stingray.
To reduce the chances of unknowing flap deployment, Futaba 8U Tx is set for Switch A to enable the flap (on throttle stick) only when the switch is down. A piezo beeper and blinking LED in series are connected to Switch A so that when it is down, the Tx beeps at the LED blink rate.

Back to Many Photos
S8 Gliders
Back to Main WSMC CD

This pagecreated on a Macintosh using PhotoPage by John A. Vink.

Assembly of Stingray 3.6 S8E model in July 2000. Stingray 3 kit bought from Nick Rivieccio. Design used Stingray 6 type fuselage, tail attachment, and nose pod Also used extended wingtips as earlier Stingray 4.6 model did	P7170042.JPG	P7170046.JPG	P7170048.JPG	P7180052.JPG
	Installation of CS-21BB servos in wing bays. Balsa glued to servo gives clearance for output arm and allows CA to be wicked-in to secure servo once laid in place against the upper wing skin.	Note upside down views which show the bottom of the wing	Servos glued into placed before covering with balsa	Balsa "patch" glued into place over left wing bay
P7180053.JPG	P7180057.JPG	P7190058.JPG	StingRay%20Wiring.GIF
Masking tape along outer edges of balsa to prevent sanding too deep when sanding balsa flush.	Fiberglassing the center section. Allowing to cure before trimming the edges and sanding the glassed area of the LE.	Minimal 4-wire arrangement going thru boom. See drawing.	This wiring saves mass, as well as space inside boom.
P7170044.JPG	P7170050.JPG	P7230001.JPG	P7230002.JPG	P7230003.JPG
Tail assembly. Pushrods not yet connected. Fiberglass reinforcement on bases of control horns not yet cured or trimmed.	Completed tail. Plastic tubng and CA was CAREFULLY used to connect "Z" bend music wire to pushrods	Completed model, with extendedtips (red).	Bagged slightly larger tail was provided by Ben Roberto, as well as nose pod and foam cores for the tips
StingRay-3.6.JPG	Next: Cuda-Flap models for S8-P event at 2001 flyoffs	Radically different layout than a true Cuda. Essentially used the wing core and skins from a Cuda and replaced everything else in the kit with either lighter parts or different layout (such as fuselage pod under wing). Wing designed for a 1 x 14" flap, deploying down 90 degrees. Wing was reinforced to make up for the structural loss of the cut-out.	Cuda-X.jpg	First Cuda model was completed in late April. But a dumb mistake caused it to crash on the first flight (Transmitter off). Other than some limited hand launches the previous day, nothing was learned from the model regarding whether the flap was worth doing.

	Assembly of fuselage pod. Engine is located so that the nozzle is about 1/4" ahead of the flap when the flap is deployed 90 degrees.	P7160002.JPG	P7160004.JPG	P7160008.JPG

Wing skins took a lot of time to mark out where to place fiberglass reinforcement and graphite strip. 3/4 oz glass cloth used, nothing heavier. Rather than the regular kit fiberglass tape for the TE, 3/4 oz glass cloth was applied to both sides of the TE, for the last 1/2" (orange area). Glass cloth was applied to the TE across a 1.5" chord for the first 8" span out from the root. This was to reinforce the last 1/2" of the main wing and to stiffen the flap against warpage.	P1010010.JPG	P1010013.JPG	1/4" wide gap was cut out from the wing core, along the flap hinge line. Gap was filled with 1/4" thick balsa cut and sanded to shape to match the upper angle of the core airfoil. Balsa was glued to the core using foam-friendly CA. When the wings were ready for skinning, red dye was used in the epoxy, looks pink when thin. Darker areas show where glass was applied. A strip of fiberglass was also added to the top and bottom of the balsa insert piece in the wing core, to further reinforce that area	CudaLayup.jpg
	Core ready and Skins marked out	Note balsa insert glued to core along flap hingeline
V-tail servos wired up for mounting side by side, flap servo by itself under wing just in front of engine. Wiring was done along similar lines as the Stingray wiring shown before. However not done to the extreme it could have been, the flap servo could have shared the same bus wires as the V-tail servos	P4260001.JPG	P7290034.JPG	P4270030.JPG	P7280017.JPG
		Fuselage with Flap servo pushrod exit visible	Flap down on Cuda-Flap#1	Flap up on Cuda-Flap#2
A second Cuda-flap model was completed to fly at NARAM. It worked out very well, the flap a great way to do S8-P. A third model was built to use at the flyoffs, the second one as a back-up.	P7280010.JPG	P7280012.JPG	P7280015.JPG	P7280016.JPG
Also made use of 150 mAh Nimh batteries, which are the same size and almost same mass as 50 mAh nicads. Great way to go, and 3rd servo made 50 mAh too iffy. Warning though, some Nimh packs under-perform. One pack tested to only around 70 mAh, good ones tested to around 130. The pack that tested to 70 not used for anything but ground tests. Sirius tester highly recommended.	1/8" balsa tail was glued to the TOP of the boom. Solved alignment problems and a very strong way to attach a tail on a model that by its nature will suffer rough landings.	Hitec 555 receiver has antenna over 36" long. Last 36" replaced by .015" music wire, allowed to extend out the back of the boom. Same solution as used for 35 mHz woes in Slovakia. .015" wire antenna proven out by Alex Seltsikas years before..	Cuda Flap models 2 and 3 weighed in at around 194-196 grams glide mass, with 555 decased receiver, 17 gram 150 mAh NIMH battery pack, and of course a 3rd CS-21bb servo. My lightest Stingray-6 was 183 grams I think, with Futaba Rx, so not bad. Just not nearly as aerodynamic as a Stingray.	To reduce the chances of unknowing flap deployment, Futaba 8U Tx is set for Switch A to enable the flap (on throttle stick) only when the switch is down. A piezo beeper and blinking LED in series are connected to Switch A so that when it is down, the Tx beeps at the LED blink rate.