HobbyKing.com New Products Flash Sale
Reply
Thread Tools
This thread is privately moderated by burkefj, who may elect to delete unwanted replies.
Old Sep 28, 2011, 01:32 AM
X-15 Jockey
burkefj's Avatar
Joined Oct 2006
2,440 Posts
I like to check the CG at this point and mark it on the model, after adding any needed nose weight.

You can paint and/or add decals at this point.
burkefj is offline Find More Posts by burkefj
RCG Plus Member
Latest blog entry: Natter
Reply With Quote
Sign up now
to remove ads between posts
Old Sep 28, 2011, 01:33 AM
X-15 Jockey
burkefj's Avatar
Joined Oct 2006
2,440 Posts
Balance the model at the CG point indicated on the plans with a loaded rocket motor in place. It may take nose weight or a larger battery to obtain this. This is safe for the first flight, it will be stable on boost and then be nose heavy on glide, be ready to put in some up trim once the motor burns out when you get to launching.

If possible do some glide tests in tall grass. Try to launch the model slight nose up as in a "mush". If the plane is stable, it will drop the nose slightly and go into a glide. If it is tail heavy it will pitch up or just keep mushing. Do not attempt to fly it in this condition.

As you get more experience you may find you can move the boost CG back slightly and be slightly tail heavy on boost and slightly nose heavy on glide. These models are quite well behaved on boost and just need minor stick input to maintain a vertical boost. On glide keep the nose down slightly to keep airspeed, plan your approach and flare near the ground to touch down tail first.

Test flights today were perfect, straight launch, and some up trim needed for glide, as expected.

I recommend a 1/4" 6 foot launch rod to ensure stability especially in windy launches and the E-6RC aerotech reload motor.
If you set at least 1" of movement for both aileron and elevator up and down, you should have plenty of throw for compensating for the nose heavy condition, in fact I didn't need as much trim as I expected.

The plans should show the liftoff CG(the most rearward cg you should have with loaded motor, and the glide CG which is about an inch ahead of this. If you do not see them marked on the plans, please be sure to do glide tests and confirm or contact me.



Good luck.

Frank
burkefj is offline Find More Posts by burkefj
RCG Plus Member
Last edited by burkefj; Nov 30, 2012 at 10:15 AM.
Reply With Quote
Old Oct 08, 2011, 08:31 PM
X-15 Jockey
burkefj's Avatar
Joined Oct 2006
2,440 Posts
Here is a video of this actual V-2 test flight before painting, I put in about 15 clicks of up trim tied to the flap switch for post burnout flight trim and it was perfect. Nice boost and easy adjustment of flight profile under burn. A4B has a very nice glide.

View in full screen for best picture, plane will get small, but you can easily see the boost and landing.

Frank

Scratch built RC A4B Winged V-2 rocket boosted glider (1 min 59 sec)
burkefj is offline Find More Posts by burkefj
RCG Plus Member
Last edited by burkefj; Nov 30, 2012 at 10:17 AM.
Reply With Quote
Old Jan 01, 2014, 04:41 PM
Registered User
Joined Mar 2011
100 Posts
Mr Burke. Do you have a material list that is common to all your builds? So I can get parts on order thanks Where do you order your rocket engine mounts?
Duke58th is offline Find More Posts by Duke58th
Reply With Quote
Old Jan 01, 2014, 08:13 PM
X-15 Jockey
burkefj's Avatar
Joined Oct 2006
2,440 Posts
Hi, here is a quick rundown on common parts I use, the foam, servos, etc are all needed, the micro horns or carbon rod may or may not be needed depending on the model.

6mm depron in 26.5x39" sheets, most will fit on one, some take two, from rcfoam.com or local hobby shops.

1/8" or .118 carbon rod or tube. Tube is slightly lighter, and can be slid onto .047 music wire pushrods to stiffen them if you are trying to put the servo weight more forward. Also from rcfoam.com or midwest or local hobby shops.

Sometimes I use .157 or .118 by .039 strips as well for reinforcing splice joints or in the tail or for spars on very narrow wings, just slit the foam, press in place and run thin ca in the joint and tape over with dubro hinge tape.

.125 ID aluminum tube, used for torque tubes for full flying tails, I get it at the local hobby shop.

.039 or .047 music wire from the local hobby shop for pushrods.

Dubro hinge tape(3M blenderm) it is useful for taping spars in place for reinforcement, or for hinge material on ailerons or delta wings.
http://www3.towerhobbies.com/cgi-bin...&I=LXJGT1&P=ML

Dubro micro servo horns, I drill these out and glue them onto the aluminum tubes to make the torque tubes for full flying tails.
They come in white and black, http://www3.towerhobbies.com/cgi-bin...?&I=LXLPF1&P=7

Thin foam safe CA and CA+ with accelerator for most glue joints.

3M-77 spray adhesive for laminating if needed.

Servos, I have used HS-55 servos for allmost all my gliders, they are light and I've had little failure using them. The hs-65 carbonite gear and HS-82 MG and HS-81's are all good too, heavier but more torque, not really needed for most of my rocket gliders.

Motor tubes, for 24mm you can use RAHMT09 from red arrow hobbies, and for the motor hook you can use, RAHEH24, which are long to fit the estes E motors, you can re-bend the hook end and cut it to fit the aerotech 24mm reload casing.
Red arrow also carries the aerotech 24mm RC casing and the E-6RC reloads.
I've also used .047 music wire doubled over and bent to shape for a motor hook as well when i ran out of estes type motor hooks. I use the dubro hinge tape to secure the motor hook to the tube with several wraps and it works fine. You don't need centering rings, etc and epoxy, there just isn't that much stress on them. Sometimes from Quest or Aerotech you can find white paper 24mm tubes which are nice becuase you may not need to paint them. I just find them at my hobby shop.

Appogee components carries the white tubing: http://www.apogeerockets.com/Buildin...tes_BT-50_size

and the motor hook pack which comes with several, http://www.apogeerockets.com/Buildin...ook_Assortment

Receivers, whatever you are comfortable with. I fly spektrum and have been using the 6115e receiver, but am switching to the AR400 now as it is full range and cheaper. A lot of guys fly orange and they seem to work fine.

BEC, I use the castle creations 10a BEC for rocket gliders for providing good current to the servos and rx, hobby king sells a cheaper one, tower has the castle unit.

Dubro micro control horns used for ailerons or delta wing surfaces, only get the kind with two prongs: http://www3.towerhobbies.com/cgi-bin...?&I=LXJGT5&P=M


Dubro micro servo mounts, they allow you to screw the servo to these little stake pieces, then you push them through the wing and use a slide on zip disk to lock them in place, I only use these when using the larger servos that need a bit more secure mounting.
http://www3.towerhobbies.com/cgi-bin...?&I=LXLPF0&P=7

Dubro self adhesive velcro, it just sticks well, so I don't bother trying to find a cheaper alternative.
http://www3.towerhobbies.com/cgi-bin...&I=LXD648&P=ML

Paint, I use model master flat black, red, OD, titanium, etc, it doesn't melt the foam, but will peel off a bit if you have to mask over it. I haven't found a better foam for direct to depron application.

Stars and Bars, 4" versions from sig manufacturing, only place I've found them.
http://www.sigmfg.com/cgi-bin/dpsmar...501.html?E+Sig

Lettering, vinyl in black 1/2, 1, 2" from staples or similar.

Self adhesive Monokote trim, tower and the local hobby shop carries it, you can cut and make all sorts of trim from it.

Pusher motors, I've used the grayson hobbies microjet V-3 with an apc 6x4 and the 20 amp speed control that comes with it, if the plane weighs about 16 ounces or less it is really good, I'm getting 6 minute run times with a 12 oz plane using only an 800mah 3s battery. The grasyon V-2 2212-06 parkjet motor is good if your plane weighs over 16 to about 25 ounces, I use a thunderpower prolite battery of 2200 3s that weighs only 5.6 ounces and get 9-11 minutes of runtime with the same 6x4 or 6x5.5 prop and the 30 amp esc that comes with the motor. If you want to run a separate ESC, I like the castle thunderbird 18 and 36 as a general rule. Grayson hobbies also carries 22, 20 and 18 ga silicone wire for the motor leads that is not very expensive and very flexible.
http://www.graysonhobby.com/catalog/...o1eqq3bhdkogu7

For smaller models I use a micro JST connector to the battery and for larger a deans plug.

If you want to make a plug in motor adapter, you can start with this: http://www.jonrocket.com/index.php?m...FQqCQgod2H8AXw

You will need to put one of the centering rings about 3/16" from one of the ends and then put the other one flush, then epoxy a ply plate large enough on the end that is flush to fit your electric motor mount. You then need to cut a notch in the ply to fit the motor hook on the rocket mount.



Quote:
Originally Posted by Duke58th View Post
Mr Burke. Do you have a material list that is common to all your builds? So I can get parts on order thanks Where do you order your rocket engine mounts?
burkefj is offline Find More Posts by burkefj
RCG Plus Member
Last edited by burkefj; Jan 02, 2014 at 04:48 PM.
Reply With Quote
Reply

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion What do you do with a foam glider, a model rocket tube, and a 50mm EDF? fredmdbud Scratchbuilt EDFs 3 May 20, 2011 06:44 AM
For Sale Phoneix Rocket Glider Chivalae Aircraft - General - Miscellaneous (FS/W) 0 Mar 23, 2011 11:56 AM