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Old Aug 13, 2009, 07:34 PM
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Joined Sep 2005
53 Posts
Gear doors

I got my new Tam gear and gear doors installed. Video:
Spark Gear Doors (0 min 50 sec)


I used servos for the gear doors and it was a chore. My doors are not that great fit and finsh-wise so I may make some new ones... but the mechanism is working great. There is very little room to work with so if anyone plans to do this it will take a lot of time... a lot of time But it is worth the end result. I am leaving the front open for now to let air in around the batteries. I might add a door that is actuated by the strut but where the wheel enters I will leave open.

In the end I used 2 Hitec thin wing servos to drive the doors. This allowed me to use Tamís mounts so I can get them out should the need arise. The tricky part is the door linkage. I used some wood standoffs connected to some BVM offset hinges (just using them as levers 0 standard hinges are on the doors.) This allows the servo to pull to open the doors. I could not get the geometry to work like Tamís using cylinders. In order for the linkages not to hit each other I made the offset for one side slightly longer so it pivots under the other side when they close. The clearance is next to nothing Ė maybe 1 or 2 mm.

To sequence the doors I used my 14mz offset mixing. I can email anyone who wants the details. The way to do it is to use a mix for opening and a mix for closing. On mix one you use a timer mode Ė this causes the door to cycle. I set a 2.5s delay in the stop position (doors open.) On the gear channel I set a 1.5 second delay to make sure the doors have fully opened before opening the gear. About 1s later the timer cycles and closes the doors. The second mix does exactly the same thing but you donít need the gear as the first mix takes care of gear open/close. This allows you to set timers and servo speeds for gear doors down and up in both the open and close position... pretty cool.

I used CA to glue everything. I will be installing small screws tonight now that it is all working correctly. The CA should be plenty strong for normal flight loads but the screws will ensure it stays intact
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Old Aug 13, 2009, 07:56 PM
Lee Liddle
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Carrollton, Tx
Joined Dec 2006
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Nice work!! Looks like it took a lot of time.....a lot of time......

I also watched the video. Thanks for taking the time to do that. Very slick!
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Old Aug 13, 2009, 08:35 PM
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San Jose, CA
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Nice works Chris.
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Old Aug 17, 2009, 04:54 PM
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Quote:
Originally Posted by Tamjets
Nice works Chris.
All Sparks need Tam's gear, struts and to be modded for gear doors.

I can't tell you what a difference the gear doors make. You can literally feel it. My jet is so fast now and so clean at low throttle. When the door pop closed you get this instant feeling of acceleration.

I am flying 5 mins, doing 7 or 8 full power bursts for passes, long humptys, huge loops etc. Cruising at 1/2 throttle most of the time... and I am using only 3,200 to 3,500 mah. The jet is so fast on speed passes now it is SCARY.

I have 800 to 1000ft of straight up vertical entering from cruise speed and rolling on to full throttle.

15 flights this weekend... it was a good one!

The best battery combo so far is the Thunder power 20c/40c 5300mah ProLite V2 FAI packs. I get great speed, excellent thrust and the batteries come down at only 101f.

The XPS 30c/50c 5000mah cells feel like they have the most thrust on verticals but I get less top-end speed (may need more cycles) and end up carrying 3oz more weight which eliminates the benefit of the extra thrust. I ended up using more throttle on verticals and consistently used 400mah per flight more as a result. Don't get me wrong for the money they are great cells but the TP 5300's seem to really hit the sweet spot for general flying for weight vs performance vs flight time. You could fly 6 or maybe even 7 mins if desired but I want to take it very easy on the packs and make them last.

I think a 10s 4000mah 30c setup would be killer for 4.5min to 5 min aerobatic flights.

I love my Spark, what an awesome plane!
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Old Aug 17, 2009, 05:16 PM
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Dublin Ireland
Joined Aug 2005
827 Posts
Nice one.....
I nearly have everything together for my Spark.Thanks to all who have answered my Questions and even went to the bother of posting pictures for me.My Spark is second hand but unflown.It was converted to turbine but I am putting it back to edf.I believe the Ducting is at last on the way from Comp Arf.When the original ducting was cut there was enough left to graft the new ducting on to it.Should i cut the new ducting to fit over the original or should i cut it to fit inside it? also Should i glass it in place .
Thanks again
Cheers
Steve.
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Old Aug 17, 2009, 05:53 PM
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San Jose, CA
Joined Jun 2006
5,453 Posts
Quote:
Originally Posted by crhammond
All Sparks need Tam's gear, struts and to be modded for gear doors.

I can't tell you what a difference the gear doors make. You can literally feel it. My jet is so fast now and so clean at low throttle. When the door pop closed you get this instant feeling of acceleration.

I am flying 5 mins, doing 7 or 8 full power bursts for passes, long humptys, huge loops etc. Cruising at 1/2 throttle most of the time... and I am using only 3,200 to 3,500 mah. The jet is so fast on speed passes now it is SCARY.

I have 800 to 1000ft of straight up vertical entering from cruise speed and rolling on to full throttle.

15 flights this weekend... it was a good one!

The best battery combo so far is the Thunder power 20c/40c 5300mah ProLite V2 FAI packs. I get great speed, excellent thrust and the batteries come down at only 101f.

The XPS 30c/50c 5000mah cells feel like they have the most thrust on verticals but I get less top-end speed (may need more cycles) and end up carrying 3oz more weight which eliminates the benefit of the extra thrust. I ended up using more throttle on verticals and consistently used 400mah per flight more as a result. Don't get me wrong for the money they are great cells but the TP 5300's seem to really hit the sweet spot for general flying for weight vs performance vs flight time. You could fly 6 or maybe even 7 mins if desired but I want to take it very easy on the packs and make them last.

I think a 10s 4000mah 30c setup would be killer for 4.5min to 5 min aerobatic flights.

I love my Spark, what an awesome plane!
Power to weight ratio is the name of the game.
I had my Spark set up with 10s 3850mAh with 1512 2Y motor last week. This set up put 3.7kw at 100A and it was hauling.
I putting another Spark together doing gear doors as well. This time no UP-2 valve and tint the canopy. No cockpit this time. I know it we be under 10 lbs with this set up.
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Old Aug 18, 2009, 02:49 AM
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Joined Apr 2009
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Hi everyone,

I haven't posted here before, mainly because I'm a bit of a newbie and there wasn't really anything I could add. Read this thread with a lot of interest while building my Spark. There aren't too many of them down here in Australia from what I can tell.

I maidened mine yesterday - what a beautiful aircraft, so smooth and fast. I'm running a Stumax EDF with 11s 4200 Hyperion VX G3 (2 x 4s, 1 x 3s). Did two flights - next Monday I'm taking it up again and will also try 12s (3 x 4s, VZ series 4500's - more weight, so we'll see how it goes).

Here's a link to video of the flight:

http://gallery.me.com/mincherallen/100086

Apologies for the sound effects and commentary from my son doing the video!

All the best,
Colin
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Old Aug 18, 2009, 10:37 AM
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110 pages allready,,,

This thread is Legendary.

This is for you Tam
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Old Aug 18, 2009, 11:24 AM
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Brentwood, California
Joined Jul 2007
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Hey Colin,
Good job on your spark! I'm loving my Stu Max/ Spark also...
what a fun plane... the really cool part is with 5000 mah I'm up to 5:30 flights and only taking out 3400 mah.. it's just effortless to get a nice long flight time with this combo... I'm in love with it

hope you get many great flights from yours

don't you just love the sound it makes
it's always fun to hear is that electric

later
Ron
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Old Aug 18, 2009, 11:47 AM
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United States, KY, Crestview Hills
Joined Dec 2000
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That was awesome Colin! I had the 9S fan and while it flew well it was never that fast.
Bob
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Old Aug 18, 2009, 12:16 PM
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Brentwood, California
Joined Jul 2007
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I'm telling you Bob mines on 11s 30c 5000 thunder Power Pro Power packs
and it's just a rocket ship... at half throttle it crusies really nice
you need to get another one, your the man that started the stu max spark craze

I don't know the top speed but would have to guess near 170 mph..
can anyone doppler Colins or is the Stu Max to quite to pick up?

later
Ron
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Old Aug 18, 2009, 12:33 PM
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Joined Sep 2000
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Very nice flight, perfect maiden.
This is the pass at 1:40
Mikael
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Last edited by Mikael; Aug 18, 2009 at 12:47 PM.
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Old Aug 18, 2009, 12:37 PM
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Joined Jul 2004
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I got 151.86 mph on 2 different passes.
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Old Aug 18, 2009, 12:42 PM
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The best pass I got was also at 1:40 and that was 167.80 mph Very nice!!
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Old Aug 18, 2009, 12:48 PM
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Brentwood, California
Joined Jul 2007
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Hey my eye has been pretty good...
I've been guessing just under 170 mph with mine... when people ask
I must have a doppler eye

I could figure my A-4 flys around 150... and the spark is so much faster

That's dam fast and not comfortable to fly at for long and it gets small in a hurry... it also gains speed in the vertical which looks cool

love it!!
can't wait to do my Fox Hawk with the Stu Max


ron
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