madmodelman

You don't lose the gear channel, it's simply moved further down the list for latency reasons. It is only a switched channel so is not as important as a fully proportional critical surface.
Just do a simple mix el to brakes and flap to flaperon for crow.

mrloudly

Ahah... "Flaperon" How have you setup your wing? I'm using the two aileron one flap setting. Guessing the flaperon scheme will give me a few more options. The Gear appears as N/A in channel assign. I've assigned an aux to gear switch A which all works fine. I want to now assign my rx gear port to run the brake solenoid via a switched mix (A) running from full down elevator. Give me a simple Heli anyday :-). Thank you for your help!
Andy M

Len Todd

For Brakes on the Elevator: I just did a mix = Elev to Brakes((Aux 3) when the Gear Switch is in the down position. I also have the brakes (Aux 3) on the right slider on my DX9. I set it up to use the slider to lock 'em and the Elevator stick to stop 'em. Being a new Transmitter, I am sure I'll have to adjust the mix a bit further once the snow melts up here. This method will not work with an electronic brake control as you would be out of air by the time you land.

BaldEagel

Switch the mix off when the gear is up then you will not be loosing air when airborne and using the elevator, if you make the mix so the brakes do not come on until the elevator is over 75% then also you will not be loosing air in normal flight if you can't do the mix, surprising how little we use down elevator, normally only in inverted manoeuvres, personally I don't like the brakes on the elevator as you are lifting the mains off the ground with down elevator and effectively decreasing the braking effect, I use a side slider on an electronic brake valve, it works for me.

MIke

Len Todd

My Elev to Brake mix is switch on when the gear goes down. However, I first installed an electronic brake valve. Given the way it works (like an ABS system, only puffing off air for proportional braking) I could only get one maybe two stops from a large can of air. I switched to a U.P. 6 brake valve and servo. Now I can get well over 10 good hard stops with the same can of air and still have 60#s left. Am I missing something here about Electronic brake valves? If I had used the Elev Stick on that Electronic valve I would have had no braking air left by the time the plane touched down.

BaldEagel

What valve is it? if its the same one I have (name escapes me at the moment) I had it set up wrong when I first installed it and had the same symptoms you describe, as soon as I read the manual (typical male) it worked perfectly and use's less air than a normal valve.

Mike

Len Todd

It is an AirPower EV-1U Single Action Proportional Brake Valve. I attached the directions that came with it.

As I understand it, there are two setup modes (i.e. On/off and Proportional). The proportional mode puffs off air to keep the brake from locking up. The on/off mode just locked the brakes up. One of our more experienced builders has the same valve and he greases the brakes to keep them from locking up. Two other experienced builders, up here, gave up trying these valves and went to the U.P. 6. So that is what I did. I figured I would frog around with it later. This jet was the first time I needed to have working brakes, so all these valves were new to me, at the time. Got any ideas?

BaldEagel

Just went up to the workshop and the valves I have been using are Jet Tronics, totally different set up and operation to yours, so can't be much help I'm afraid.

Mike

Si_B

Tried balancing my Sprint today but my balancer just doesn't fit the model. Made up some ply plates to fit over the aluminium rods and strung the model up with string around the 255 c of g mark and she balances slightly nose heavy(with booms and tail on, plus full header and wheels down). If I balance her on the main spar, she is slightly tail heavy, so I'm guessing I must be somewhere in between. Should I be good to go? Everything else tested and set up ready for her maiden next weekend.

I'm only concerned as I took a shed load of lead out of the nose from the previous owner who I think was running a much heavier turbine than my Wren 80.

Cheers,
Simon

Len Todd

Does anyone worry about temporarily covering for flight the holes in the wings and stab where the screws go in?

BaldEagel

No, but what I have done is put a piece of carbon tube in the wings to stop the bolts from falling inside the wing.

Mike

memejfd

Hello,
I am in the process to finalise my boomerand sprint before maiden.
When putting the wings on, i noticed that my tail was not fully parallel to the wings. It comes from the CF spar which is not tight enough in its tubes. So i did put some tape around it to have a better fit. Tail is nearly parallel now (but not 100%).
Did anyone had this issue ? Any other idea to have this tail fuly parallel with the wings (otherwise it will take some aileron trimming i am afraid).
Thanks in advance
Best regards.
JF

chris1971

If i understand what you are saying, you could put a washer or spacer on the bottom of the stab on the low side to shim the height of the low side of the stab. The stab sits on the booms and shimming the low side should raise it to make it parallel. Hope this answers your question and helps.

Si_B

Are your booms parallel to one another? If not, maybe adding some alignment dowels between the booms and the inner wing might work if there is too much play during assembly.

Downwind3Zero

My Feedback: (10)

Now that's a great solution!!
Chris

BaldEagel

I think in the end everyone with a Boomerang has dropped the wing fixing bolts inside the wing cavity, something that on the field we know is going to happen eventually, its the details that make it easier, glad I could help, but even though I thought of it myself ten or so years ago, I doubt if its a first.

Mike

INDIZA

https://m.youtube.com/watch?v=srNg1-UO12Y&feature=youtube_gdata_player This is my Boomerang Sprint flown by my son with dreamworks retracts savox servos and Kingtech K80 kero.

Len Todd

Mine was maidened today. Looks like 19 ozs of lead in the nose worked well with a P-90 RXi and two Spektrum 2000 mah receiver packs and the OEM LiFEPO4 battery tucked upfront. Roller 'er over and she stayed straight as an arrow. For landing, the Flaps at ~45 degrees slowed it nicely w/o much ballooning. (After the flight, I changed the down elevator from 10% to 15% on the Flap setup.) No need for crow. Brakes on the down elevator when the gear is down and the slider worked really well. Used the slider to lock them for starting and the Ele Stick for stopping. The 10-12 mph winds did not bother this jet at all, even when landing.

xxq111

Hello!
Have been offered a boomerang which are for sale.
It is equipped with Dreamworgs E-landing gear, BVM uta, booma pin / flag switch
and Hitec 645.


Are these servos good enough for Sprint?


The turbine will be a Jetmunt VT80.


Regards
Sejenssen

BaldEagel

Not that there is anything wrong with the HS645, but they are analog servo's if that is the number on them, I think the latest digital servo's are HS5645's, if they are old it may be worth checking them out before you buy.

Mike

lxfly

As Mike stated, if they are old change them, otherwise I think Sprint is not ambitious and if the owner has flown it regularly, the setup should be ok for starting, just use a 6V power supply.
We are flying Sprint and some similar models with P100 and Graupner DES 707 BB (ok it's digital) with no problem.

xxq111

Hello!
The model is only 6 months old.
How old servos is I do not know.
Some opinion of good but reasonable priced digital servos to Sprint.


I have used Hitec servos for 21 years, other suggestions?


Regards
Sejenssen

Vettster

Ive been using Blue Bird servos for the past 4-5 years now. There in all my jets and giant gassers. Never had a glitch and center very well. This link is to the ones I have in my ailerons but offcoarse there are many different torques available. About $20 each
http://www.hobbyking.com/hobbyking/s...7sec_52g_.html

stegl

Started reading this forum from page 1 and now at page 64 and my Sprint and Dreamworks Pro gear arrived yesterday. Everything arrived in pristine condition. From what I am aware of I was very fortunate to get the last Sprint in North america. After what I have read it looks like I am going the route of the Jets Munt VT80 for power because of its lighter weight over the Kingtech K80 . Have a question .... Has anyone ever used or considered using rudder Crow setting for additional braking ? (This would be were each rudder swings outward to create additional drag ).
another question.... Should the electric brake plug be mounted do the plug is behind the gear strut ? Can't seem to find anything in the instructions .

as for servos , Will be going with all Airtronics digitals . The other issue with the Sprint servo covers is that the mounting lugs are not long enough for the 20 mm wide servos short by abou 2 to 3 mm . What did you fellas do ? Thanks in advance.

BaldEagel

First off the servo mounts just need a bit of trimming to fit the servo's, If I remember correctly the inside face of the arms have a small nib front and back vertically on the arms, I just cut the nibs off.

The Sprint does not need rudder brakes, with the flaps and ailerons set up to a crow configuration it will land very slow and short, in fact once on its final approach with all the drag producing bits set you need power to fly the Sprint to the runway, once over the runway just close the throttle and she will settle down by herself with a bit of up elevator, I have the crow set up on a side slider, from the off position to half way I get half flap, from half way to the bottom position it gradually brings in the up aileron and flap to about 80degs down, this produces a lot of drag and slows it right down, that's why you need a bit of throttle to get to the threshold, I think DW uses rudder bakes in addition, but I have not found it necessary on our short grass runway.

Can't help on the electric brakes as I use old fashioned (now) air.

Mike

Mike