Semroc Hawk: I suck at gliders

[Solomoriah]

So I got a Hawk as a bonus on an order last year, and despite my poor results with gliders, I built it anyway. Wednesday I flew it for the first time, and it nose dived. So... what do I do to fix that?

[Bob H]

So I got a Hawk as a bonus on an order last year, and despite my poor results with gliders, I built it anyway. Wednesday I flew it for the first time, and it nose dived. So... what do I do to fix that?Nose dived in boost or in glide?

If glide, add some weight to the tail.

[Scott6060842]

Add weight to the tail? I'm assuming that you trimmed it out before flight.

My understanding is that the Semroc Hawk performs best when built without sanding sealers, paint, or primers that weigh it down.

I finished mine using permanent markers.

[sandman]

So I got a Hawk as a bonus on an order last year, and despite my poor results with gliders, I built it anyway. Wednesday I flew it for the first time, and it nose dived. So... what do I do to fix that?

OK, now listen carefully.

This is from years of trimming stick and tissue rubber band airplanes.

When making adjustment for glide make one and only one change per trial!

I cannot stress this enough. Otherwise it will just be another lesson in frustration.

Add or subtract weight, do several test tosses to see what it does remembering what you just adjusted.

If that does not work go back to the original setting, if you added weight take it off.

Then try one more adjustment either ellevon, rudder, weight whatever but ONLY ONE change!

If that doesn't work go back to the previous sett.

After a while you will get the hang of it but you have to keep going back to your original setting almost every time.

[AstronMike]

Sandman's trimming info mirrors my own, and some of you on here *KNOW* how that can be!

What I'd suggest for such a small glider is to use an 'easy' trimming weight, most likely a small paper clip. From the sound of your post, just place this over the tail, preferably on the underside of the rudder. Test toss....multiple times. If the bird is now stalling, move the small clip to a point more forward. Test again.

You should likely 'hit' what looks like a good trim point soon enough. Im also assuming that you *DO* have some decalage in the stab, right? If not, and it is a 0-0 config, then you may have unmitigated h*ll trying to 'lock in' a valid trim. If you seem to be stuck between stall and dive with only the slightest weight shift, then you are in this boat.

One 'hack fix' for such a deal is to add VERY SMALL elevon tabs to the stab, one on each size. Just use tape, fold it over itself, leaving no more than 1/8" extending beyond the aft edge of the stab. Bend these up slightly, and toss. You may find you need that small paper clip now as NOSE weight, and this is actually preferred. IN no case should you have to bend the 'elevonettes' up much at all, or youll throw off the boost for sure.

Now, if you really want to build a no frills cannot miss glider, please dig up my SkyDart LV plans and info on this Forum. Slap one of these together and you will wonder where stuff like this has been for so long.....

[ghrocketman]

Totally agree with the advice from Sandman.
ONLY make one change at a time...otherwise you will never know which change made the difference.
Gliders are not THAT hard...you just have to be patient with them and always trim before first flight.

[Solomoriah]

Add weight to the tail? I'm assuming that you trimmed it out before flight.
That would be a bad assumption.

Seriously, I suck at gliders. The last two I built, both of which are now lost, I killed hours trying in vain to trim... probably because, despite the best of explanations, I really don't understand what I'm doing.

Up I do good. Parachutes I do good. Gliders I suck at.

My understanding is that the Semroc Hawk performs best when built without sanding sealers, paint, or primers that weigh it down.

I finished mine using permanent markers.
I took that to heart with my Tinee... and I don't have it anymore. Not that it glided... it nosedived, actually, right into a beanfield.

When making adjustment for glide make one and only one change per trial!

I cannot stress this enough. Otherwise it will just be another lesson in frustration.
Gah. STILL a lesson in frustration. As I mentioned, I spent a lot of time trying to trim two other gliders. Admittedly, one was a Sparrow, which I'm told is hard to trim. Paradoxically, it actually sort of glided, though not well, and was lost on its second flight.

Now, if you really want to build a no frills cannot miss glider, please dig up my SkyDart LV plans and info on this Forum. Slap one of these together and you will wonder where stuff like this has been for so long.....
Hmm. I might just have to do that.

[GuyNoir]

Here's a spot with some clear tips / hints:

http://www.gryffinaero.com/models/ffpages/tips/hlgtips.html

Or look at stuff for catapult gliders like the attached PDF.

[nvrocketeer]

Sounds like the motor failed to eject.

[Solomoriah]

Nah, I saw it eject, and it was absent when the rocket was on the ground.

Guy, I printed out that web page, but I haven't had time to read it over yet. Thanks!

[gdjsky01]

Nah, I saw it eject, and it was absent when the rocket was on the ground.

Guy, I printed out that web page, but I haven't had time to read it over yet. Thanks!

Not that it will be any comfort, but IMO you can not fail at a Deltie. You just can't. You mark the body where Rob says to in the instructions. You get it to balance right there. It will glide. You can tweak it with clay after the first launch, but if you build it like he writes, and you balance it at the mark he has you make, it will glide. My last one required nothing. No weight. It just worked.

I have built 3 of them and lost 2 :eek: :( . But both were lost to the Rocket Gods who flew them to their temple in the sky! :chuckle: :chuckle:

My third one I learned to
A) Clone the glider from a newly bought kit since after buying it 3 times, I have paid my dues :rolleyes:
B) Weight one side just a little to get it to turn. Last time out on a 1/2A - 32 seconds IIRC.

Seriously. I can not see how if you follow Robs instructions, anyone can fail at a Deltie. I know that is probably irrelevant to this thread... but to others reading it in the future, perhaps not.

[jeffyjeep]

Mary painted my freebie Hawk for me. I've not flown it--it probably weighs a ton from the sealers and paint.

Hence:

[Bob H]

Mary painted my freebie Hawk for me. I've not flown it--it probably weighs a ton from the sealers and paint.

Hence:I don't see any airfoil on that wing. :eek:

[Solomoriah]

According to the instructions, airfoiling is optional for the Hawk, although it is recommended to round the fin edges.

Not that I know a darn thing about the subject... that is the point of this thread.

[blackshire]

Boost-gliders *will* glide with un-airfoiled, flat plate wings, but airfoiling the wings and (optionally) the horizontal stabilizer (or the small forward canard wing, on a canard glider) will improve the glider's performance. A boost-glider with flat-plate wings can be used as a "foul-weather B/G," on days when a better-gliding B/G with a lower sink rate might glide out of sight.

[blackshire]

According to the instructions, airfoiling is optional for the Hawk, although it is recommended to round the fin edges.

Not that I know a darn thing about the subject... that is the point of this thread.None of these things are as critical as you may think. Not only do flat plate wings work (although not as well as airfoiled ones), but even symmetrical airfoils (those typically used in balsa fins; they produce zero lift at an angle of attack of 0 degrees) work well in boost-gliders and rocket gliders--they only need to be mounted at a slight angle to the glider's fuselage. (Aerobatic airplanes--model and full-size--often use symmetrical airfoil wings as well.) Also:

Please read the chapter about boost-gliders (B/Gs) and Rocket Gliders (RGs--he also explains about using symmetrical as well as flat-bottomed airfoils in these models) in G. Harry Stine's "Handbook of Model Rocketry" (and also see "Centuri TIR-24, Model Rocket Lifting Bodies," see: http://www.spacemodeling.org/jimz/tir-24.htm , http://www.spacemodeling.org/jimz/tr/tir-24.pdf , and http://sargrocket.org/documents/Resources/Centuri/tir-24.pdf [these are three copies of the same--just two-page--Technical Information Report]), and:

"Estes Technical Report TR-4 Rear Engine Boost Gliders" (see: https://www.modelrockets.nl/downloads/educatie/download/TR-4%20Rear%20Engine%20Boost%20Gliders.pdf ) and "Estes Technical Report TR-7 Front Engine Boost Gliders" (see: http://www.ninfinger.org/rockets/EstesTR7.pdf ) are very helpful--and a later, revised Estes B/G publication can also be accessed here (see: https://estesrockets.com/wp-content/uploads/Educator/2266_TR_4_Boost_Gliders.pdf [this is the new "Estes Educator TR-4 Model Rocket Technical Report Boost Gliders," which covers all--or nearly all--B/G and RG types], *and* https://www.google.com/search?q=Estes+Technical+Report+TR-4+Rear+Engine+Boost+Gliders&rlz=1C1RXQR_enUS985US985&ei=f85aY_26EJHH9AO5woSwBw&ved=0ahUKEwi99pXLhYH7AhWRI30KHTkhAXYQ4dUDCBA&uact=5&oq=Estes+Technical+Report+TR-4+Rear+Engine+Boost+Gliders&gs_lcp=Cgdnd3Mtd2l6EAMyBQgAEKIEMgUIABCiBDIFCAAQogQyBwgAEB4QogQ6CAgAEKIEELADOgoIABAeEKIEELADOgoIIRDDBBAKEKABSgQIQRgBSgQIRhgAUOwIWOxhYKOLAWgBcAB4AIABnwGIAfUHkgEDMC43mAEAoAEByAEEwAEB&sclient=gws-wiz [which shows various old and new B/G and RG kits]). All of the Estes Technical Reports are also included in their "Classic Collection" (see: https://estesrockets.com/wp-content/uploads/Educator/2845_Classic_Collection_TR-TN.pdf ). Also:

Boost-gliders (B/Gs) separate the motor (or the motor pod, or an entire rocket in its own right [with parasite B/Gs]) from the glider portion of the model. Rocket gliders (RGs) don't separate *anything* in flight; what goes up glides back, as a single unit, including the spent motor or motors (clustered--and even staged--B/Gs have been built and flown [there is--or was--a clustered Edmonds B/G kit]; front motor models like the Estes Falcon are also easy to cluster or stage). As well:

The B/G & RG chapter in Stine's "Handbook of Model Rocketry," Centuri TIR-24, and the three Estes B/G and/or RG Technical Reports explain ^why^ and *how* boost-gliders and rocket gliders fly--and stably--in both flight modes ([1] vertical, rocket-powered ascent, and [2] the horizontal, un-powered glide back down to the ground), and how they transition from the first flight mode to the second one. None of these things are as complicated as they may sound (Stine even included a set of simple, basic B/G design rules in that chapter of his "Handbook of Model Rocketry"--the resulting model looks very much like the MPC--and later Quest--Flat Cat kit, which he designed [his Unicorn contest B/G was rather similar, but had a V-tail, see: http://www.ninfinger.org/rockets/ModelRocketry/Model_Rocketry_v02n06_03-70.pdf and https://www.rocketreviews.com/planglider-180703153800.html ].) No one need "suck at gliders."

[blackshire]

Also, ^here^ (see: http://www.ninfinger.org/rockets/catalogs/estes_techman/esttech.html & http://www.ninfinger.org/rockets/catalogs/estes_techman/esttech12.html ) are the plans for the Sky Slash II front motor boost-glider. It is similar to the Estes Astron Falcon kit, but it has a larger wing area (and a flat, thicker sheet balsa fuselage [a scaled-down Sky Slash for 13 mm mini motors should also have high performance]); the Falcon kit's design was developed to use less sheet balsa than the Sky Slash II, yet have a high gliding performance (see: http://www.ninfinger.org/rockets/nostalgia/69est036.html & http://www.ninfinger.org/rockets/catalogs/estes73/73est28.html ), and:

The Semroc (originally AMROCS) Hawk boost-glider kit was/is similar to Estes' Falcon (see: https://www.rocketreviews.com/semroc-astronautics-corporation-hawk--by-hans-quotchrisquot-michielssen.html ^and^ https://plans.rocketshoppe.com/amrocs/amr101-150/amr101-150.htm [this link is to scans of the AMROCS Hawk kit instructions--and its parts patterns]). The Estes Falcon kit instructions and parts patterns are *here* (see: http://www.spacemodeling.org/jimz/estes/k-13.pdf , http://www.spacemodeling.org/jimz/k-13.htm , and https://outerzone.co.uk/plan_details.asp?ID=12328 ). In addition:

Here (see: http://www.ninfinger.org/rockets/nostalgia/69est072.html ) is more boost-glider information, in the "Estes Model Rocket Manual" (the "yellow pages," beginning *here*: http://www.ninfinger.org/rockets/nostalgia/69est048.html ), in the 1969 Estes Catalog. None of these things are as critical as you may think. Not only do flat plate wings work (although not as well as airfoiled ones), but even symmetrical airfoils (those typically used in balsa fins; they produce zero lift at an angle of attack of 0 degrees) work well in boost-gliders and rocket gliders--they only need to be mounted at a slight angle to the glider's fuselage. (Aerobatic airplanes--model and full-size--often use symmetrical airfoil wings as well.) Also:

Please read the chapter about boost-gliders (B/Gs) and Rocket Gliders (RGs--he also explains about using symmetrical as well as flat-bottomed airfoils in these models) in G. Harry Stine's "Handbook of Model Rocketry" (and also see "Centuri TIR-24, Model Rocket Lifting Bodies," see: http://www.spacemodeling.org/jimz/tir-24.htm , http://www.spacemodeling.org/jimz/tr/tir-24.pdf , and http://sargrocket.org/documents/Resources/Centuri/tir-24.pdf [these are three copies of the same--just two-page--Technical Information Report]), and:

"Estes Technical Report TR-4 Rear Engine Boost Gliders" (see: https://www.modelrockets.nl/downloads/educatie/download/TR-4%20Rear%20Engine%20Boost%20Gliders.pdf ) and "Estes Technical Report TR-7 Front Engine Boost Gliders" (see: http://www.ninfinger.org/rockets/EstesTR7.pdf ) are very helpful--and a later, revised Estes B/G publication can also be accessed here (see: https://estesrockets.com/wp-content/uploads/Educator/2266_TR_4_Boost_Gliders.pdf [this is the new "Estes Educator TR-4 Model Rocket Technical Report Boost Gliders," which covers all--or nearly all--B/G and RG types], *and* https://www.google.com/search?q=Estes+Technical+Report+TR-4+Rear+Engine+Boost+Gliders&rlz=1C1RXQR_enUS985US985&ei=f85aY_26EJHH9AO5woSwBw&ved=0ahUKEwi99pXLhYH7AhWRI30KHTkhAXYQ4dUDCBA&uact=5&oq=Estes+Technical+Report+TR-4+Rear+Engine+Boost+Gliders&gs_lcp=Cgdnd3Mtd2l6EAMyBQgAEKIEMgUIABCiBDIFCAAQogQyBwgAEB4QogQ6CAgAEKIEELADOgoIABAeEKIEELADOgoIIRDDBBAKEKABSgQIQRgBSgQIRhgAUOwIWOxhYKOLAWgBcAB4AIABnwGIAfUHkgEDMC43mAEAoAEByAEEwAEB&sclient=gws-wiz [which shows various old and new B/G and RG kits]). All of the Estes Technical Reports are also included in their "Classic Collection" (see: https://estesrockets.com/wp-content/uploads/Educator/2845_Classic_Collection_TR-TN.pdf ). Also:

Boost-gliders (B/Gs) separate the motor (or the motor pod, or an entire rocket in its own right [with parasite B/Gs]) from the glider portion of the model. Rocket gliders (RGs) don't separate *anything* in flight; what goes up glides back, as a single unit, including the spent motor or motors (clustered--and even staged--B/Gs have been built and flown [there is--or was--a clustered Edmonds B/G kit]; front motor models like the Estes Falcon are also easy to cluster or stage). As well:

The B/G & RG chapter in Stine's "Handbook of Model Rocketry," Centuri TIR-24, and the three Estes B/G and/or RG Technical Reports explain ^why^ and *how* boost-gliders and rocket gliders fly--and stably--in both flight modes ([1] vertical, rocket-powered ascent, and [2] the horizontal, un-powered glide back down to the ground), and how they transition from the first flight mode to the second one. None of these things are as complicated as they may sound (Stine even included a set of simple, basic B/G design rules in that chapter of his "Handbook of Model Rocketry"--the resulting model looks very much like the MPC--and later Quest--Flat Cat kit, which he designed [his Unicorn contest B/G was rather similar, but had a V-tail, see: http://www.ninfinger.org/rockets/ModelRocketry/Model_Rocketry_v02n06_03-70.pdf and https://www.rocketreviews.com/planglider-180703153800.html ].) No one need "suck at gliders."