BVM Balsa Bobcat, build photos..
02-15-2017, 03:55 PM
#51
Thread Starter
... And we were all thinking 'this guy is a bit crazy!!" I have witnessed two Balsa Bobcats fitted with Jetcat P60.. They both fly great, are grass capable, and surprisingly fast. They do take a bit longer to accelerate, and the vertical is not quite as good, but still very impressive air planes.. The Balsa Bobcat was designed for the small size motors like the RAM 500 and P-60..
03-27-2019, 07:12 AM
#53
Hey Roger-
Your bobcat xl seems to be the only one I can find running smoke internally. I was wondering if you could tell me what tanks you used to do this and where you put them? I see you are running a different main fuel tank as well(maybe that's the key to fitting smoke?). Nice build thread btw..
Your bobcat xl seems to be the only one I can find running smoke internally. I was wondering if you could tell me what tanks you used to do this and where you put them? I see you are running a different main fuel tank as well(maybe that's the key to fitting smoke?). Nice build thread btw..
03-28-2019, 09:26 PM
#54
Thread Starter
Hi,
I actually removed the smoke system on the Bob Cat after a few flights. I just could not get the density of smoke that my Bandit used to make, even though the set up used the same pump and injector. It may be the enclosed duct of the Bandit helps.
Anyways, my Bob Cat has the standard BVM Kevlar wing tanks for fuel supply. These are hidden inside the wings. You can just see the round aluminium fuel connection of the port wing.
The Smoke tank was a round plastic (possibly Sullivan) type. This was fitted in the space behind the canopy. (Turtle deck ??) It holds about 750ml. I have since plumbed it as a fuel tank, and can get 10 min + flights as I have nearly 3 liters on board.
.
I actually removed the smoke system on the Bob Cat after a few flights. I just could not get the density of smoke that my Bandit used to make, even though the set up used the same pump and injector. It may be the enclosed duct of the Bandit helps.
Anyways, my Bob Cat has the standard BVM Kevlar wing tanks for fuel supply. These are hidden inside the wings. You can just see the round aluminium fuel connection of the port wing.
The Smoke tank was a round plastic (possibly Sullivan) type. This was fitted in the space behind the canopy. (Turtle deck ??) It holds about 750ml. I have since plumbed it as a fuel tank, and can get 10 min + flights as I have nearly 3 liters on board.
.
04-02-2019, 02:12 PM
#58
Roger -
So you were using the main center as a smoke tank? I'm not not sure I'll be able to do that as I plan to run a 120 in mine. Hopefully I can stick a small little 8oz in the back behind the center tank. I get to pick up my XL this week so I guess I'll find out soon enough!
Jose-
That is a really neat scheme on the bobcat!
So you were using the main center as a smoke tank? I'm not not sure I'll be able to do that as I plan to run a 120 in mine. Hopefully I can stick a small little 8oz in the back behind the center tank. I get to pick up my XL this week so I guess I'll find out soon enough!
Jose-
That is a really neat scheme on the bobcat!
04-02-2019, 08:46 PM
#60
Thread Starter
04-16-2019, 08:17 PM
#63
My Feedback: (1)
Whatever Uncle Bob listed, with an AMT Mercury mines been flying since 2004, I sold off more than 12 jets over the years but I still love the XL Bobcat, I even sold off a Composite BC because the XL just looks cooler with its sleeker body style. This season I hope to try out a Kingtech K85 I got in a trade for a Wren44. Wether its an improvement I should know right away with knifedge I hope to improve with more speed as the Mercury tops out at 180mph.
04-20-2019, 07:06 PM
#64
Wow this is a seriously interesting thread regarding elevator servos on the bobcat that I found from 2003. It seems nearly 10 bobcats from this thread alone went in due to elevator ineffectiveness/servo torque related problems. I think I will definitely be upgrading servos to mks hbl6625(113oz torque @6.0v) and making sure my linkages are setup to be as effective as possible. It appears some were even modding the elevator for 8411s!
http://www.rcuniverse.com/forum/rc-j...-servos-4.html
http://www.rcuniverse.com/forum/rc-j...-servos-4.html
04-21-2019, 07:15 AM
#65
My Feedback: (4)
Elevator servos
Wow this is a seriously interesting thread regarding elevator servos on the bobcat that I found from 2003. It seems nearly 10 bobcats from this thread alone went in due to elevator ineffectiveness/servo torque related problems. I think I will definitely be upgrading servos to mks hbl6625(113oz torque @6.0v) and making sure my linkages are setup to be as effective as possible. It appears some were even modding the elevator for 8411s!
http://www.rcuniverse.com/forum/rc-j...-servos-4.html
http://www.rcuniverse.com/forum/rc-j...-servos-4.html
Patrick
04-29-2019, 06:51 PM
#67
Thread Starter
Wow this is a seriously interesting thread regarding elevator servos on the bobcat that I found from 2003. It seems nearly 10 bobcats from this thread alone went in due to elevator ineffectiveness/servo torque related problems. I think I will definitely be upgrading servos to mks hbl6625(113oz torque @6.0v) and making sure my linkages are setup to be as effective as possible. It appears some were even modding the elevator for 8411s!
http://www.rcuniverse.com/forum/rc-j...-servos-4.html
http://www.rcuniverse.com/forum/rc-j...-servos-4.html
Heh Heh.. Cool RCU thread from 16 years ago. Lots of vitriol and nonsense, with some gems of good information thrown in. Somethings never change I guess. I believe that both of Dave Gladwins Bob Cats are still flying..
I also use 2 of the thin wing digital MKS servos. Not sure of the torque, but there are a step up from the 3301s
04-30-2019, 10:12 AM
#68
Heh Heh.. Cool RCU thread from 16 years ago. Lots of vitriol and nonsense, with some gems of good information thrown in. Somethings never change I guess. I believe that both of Dave Gladwins Bob Cats are still flying..
I also use 2 of the thin wing digital MKS servos. Not sure of the torque, but there are a step up from the 3301s
I also use 2 of the thin wing digital MKS servos. Not sure of the torque, but there are a step up from the 3301s
Yes, my two Bobcats ARE still flying over 700 flights between them and still going strong.
My standard Bobcat, with the PST 600 ( flawless engine) was out a couple of weeks ago.
My XL which flew in Australia with a Jetcat 70 flew for a while with a JetsMunt 100 , wow ! ( rotate to the vertical after lift off )
Having borrowed the Merlin for my Rotkoski Sabre it is now powered by a Wren Supersport, perfect !
Very much a “go to “ model.
Give my best regards to the jet guys in Australia. Many happy memories of flying with you.
David.
05-01-2019, 12:59 AM
#69
It would be wise to change your servos. The recommended servos are very weak for their job. I lost a bobcat to elevator failure and when I built a new one I put in 150+ oz metal gear servos. Todd Witkoff did make some formed plastic covers a while back which covered the servos since they stuck out of the bottom of the elevator.
Patrick
Patrick
Entirely agree. I got a lot of unpleasant flack when I suggested many years ago that the elevator servos recommended by BVM were insufficient.
I installed JR 9411s on my elevators and rudders, the are still in and I have not experienced any elevator softness even when flying the XL with the Merlin installed.
Several guys who HAD experienced elevator problems followed my recommendations and the problem went away.
So, my Bobcats, now in their 18th season, fly with 9411s on elevators and rudders with 8411s on ailerons, never a moments trouble.
05-20-2019, 01:41 PM
#70
Well, my XL is finally finished, minus the smoke system! I figured I will fly it first and add it on later once I know it flies well. Little heavy at 21.5lbs, but I think it will be fine with 30lbs thrust! Now just waiting for a nice day to fly it
Last edited by txshan130; 05-20-2019 at 01:46 PM.
05-21-2019, 04:56 PM
#71
Join Date: Oct 2006
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clear canopy change the look
jose
05-26-2019, 08:33 AM
#73
Thanks all! I was finally able to get in 2 good flights yesterday. Its smooth and FASSST! Only thing is I think my CG is a little too forward right now because I felt like I didnt have as good elevator authority as my BC Composite has. But I see some folks are over an inch back behind the factory cg so I guess I will need to start moving it back. Hopefully that'll help..
05-27-2019, 01:21 AM
#75
Nice pictures, Alistair. Thank you and to Roger, the Sedgemore club and JAM for the event.
2 flights on each BobCat before rain stopped play.
Both machines are flying with C of G just a little aft of that recommended by BV.
The standard BobCat is exactly as per plan, except for the elevator servos as suggested earlier. The original wire legs were never used, Durostruts far better.
The XL is standard except as above. However the Duro strut, and the retract unit side frames, were taking a hammering on our grass strip in Australia and were replaced with Jet 1A trailing link struts. Problem solved.
The PST 600 has given really excellent service and is perfect for the standard. BC with 14 pounds of thrust. Its no sluggard.
The XL had 270 flights with a JetCat p70, later replaced with a JetsMunt 100 Merlin, fantastic performance with 22 pounds of thrust, more would be very risky with potential flutter onset if flown at full throttle
It now flies with a Wren supersport, 18 pounds, but with high exhaust velocity, just perfect.
Both model fly with Weatronic receivers with gyro functions on rudders, n/ s and ailerons.
I know the original concept of the BC was to keep everything simple but I do think the addition of flaps and reducing the aileron span would be worthwhile, further reducing takeoff, landing and approach speeds.
After 18 years and many hundreds of trouble free flights, I still really enjoy the BobCat, a great, classic jet model which I intend to fly for many years to come.
David G.
2 flights on each BobCat before rain stopped play.
Both machines are flying with C of G just a little aft of that recommended by BV.
The standard BobCat is exactly as per plan, except for the elevator servos as suggested earlier. The original wire legs were never used, Durostruts far better.
The XL is standard except as above. However the Duro strut, and the retract unit side frames, were taking a hammering on our grass strip in Australia and were replaced with Jet 1A trailing link struts. Problem solved.
The PST 600 has given really excellent service and is perfect for the standard. BC with 14 pounds of thrust. Its no sluggard.
The XL had 270 flights with a JetCat p70, later replaced with a JetsMunt 100 Merlin, fantastic performance with 22 pounds of thrust, more would be very risky with potential flutter onset if flown at full throttle
It now flies with a Wren supersport, 18 pounds, but with high exhaust velocity, just perfect.
Both model fly with Weatronic receivers with gyro functions on rudders, n/ s and ailerons.
I know the original concept of the BC was to keep everything simple but I do think the addition of flaps and reducing the aileron span would be worthwhile, further reducing takeoff, landing and approach speeds.
After 18 years and many hundreds of trouble free flights, I still really enjoy the BobCat, a great, classic jet model which I intend to fly for many years to come.
David G.
Last edited by David Gladwin; 05-27-2019 at 01:32 AM.
