JAS-39 Gripen Owners/Build Thread
04-13-2015, 12:31 PM
#1226
It was a solid weekend of filling, sanding, priming, and PAINTING. Yes, color paint finally hit the Gripen. The upper & lower grey colors look different in all my documentation photos so I was really wondering what the plane would look like to the naked eye. According to the information provided by SAAB, the upper color is Fed Std 595 approx FS36173 and the lower color is approx 36373. I'm not too sure about the "approx" so I got 36173 (which seems to have a purplish tinge) and 36373 basecoat from Tailor Made Decals along with all the dry transfers and paint masks.
I handn't yet blended the junction between the inlets & fuselage nor around the nose gear doors so I painted from the canard axles rearwards. My new Sata Minijet airbrush was delayed (I get it today) so Tony Quist kindly lent me his. I used approximately 150 mL (5 oz) of the light grey to do the underside of the plane and the pylons but only about 3oz to do the top of the plane. I was going for a really lightweight paint job so I was putting the paint on very carefully. It is a bit thin in a couple of places so I will have to touch it up a bit.
Sunday morning I reassembled the plane and went flying at my home field, the Sun Valley Fliers, on the north side of Phoenix. The take off runs at the lakebed were quite long (approx 700 ft) and the last time at the lake bed, I had six take off attempts but only 3 takeoffs so I was quite concerned that the plane wouldn't take off in time (700 ft runway at SVF) and I would go into the overrun. As such, I turned up the canards and elevators a bit. I had also fitted the custom main wheels and tires from Thomas White which have very low rolling resistance. In a pre-flight meeting with Tony Quist and Brian O'Meara (who was also present at the lake bed for the maiden and 2nd flight), we decided that the take off technique would be to hold full up elevator (like a Bandit), advance throttle to full to get the plane up to speed quickly then pull the throttle back to 2/3, watch for the nose to get light, ease out of elevator and flip to fly mode and HOPEFULLY, the plane would lift off nice and gentle. That was the plan.
Well, the plane accelerated rapidly (awesome power in the K210) into the 8 kt headwind and (it was later reported) was light on the nose in less than 200 feet. I certainly wasn't expecting that and wasn't even looking for it. I had the power back to 2/3 by this point and the plane rotated in front of us (~300 ft) and did the Gripen leap. I was so surprised that it took a few seconds to flip the switch to fly mode, get the plane leveled, and advance the throttle and by that time the plane lost 10-20 ft of altitude. The power kicked in and all was fine. I was back to 2/3 throttle by the time I turned downwind.
Essentially all of the flight was between 1/2 and 2/3 throttle with the exception of a big Split-S where I went to full power for the climb. The plane flies well and has great presence in the air. Here are a few flight shots. The right main landing gear door was held open by the airstream (at least at the beginning of the flight) but eventually closed. I'll keep an eye on that to see if I need to upsize the cylinder. The retract hydraulic system seemed to have no problems lifting the heavier scale tires.
The landing approach was done without the speedbrakes. I was hesitant to pull the power back too much and the first approach was too high so I went around and reduced the power to a lower setting for the next approach. I misjudged the approach a bit and was lined up to land off the far side of the runway so I tried to hold the plane off the ground with the nose high and add a bit of power to float it over the asphalt. The plane really was a floater and was flying quite slowly but I didn't add quite enough power and it touched down just beyond the edge of the runway and rolled onto the asphalt. OK, I'll take that.
I inspected the gear and found a crack in the wood mount for the left drag link trunion that was quickly fixed with Hysol. The E-clip had popped off the right drag link trunion and I didn't have a spare so I was done for the day. :-( On the way home, I went by ACE Hardware and picked up some 5mm E-clips so the plane is good to go for the next day of flying. In the mean time, I added some more scale details to the plane (taxi light on the forward nose door, and an exhaust duct in a cutout on the bottom of the plane).
Regards,
Jim
P.S.: Many thanks to Tony Quist and Brian O'Meara for their council and to Uncle Joe Balabon for the flight photos.
I handn't yet blended the junction between the inlets & fuselage nor around the nose gear doors so I painted from the canard axles rearwards. My new Sata Minijet airbrush was delayed (I get it today) so Tony Quist kindly lent me his. I used approximately 150 mL (5 oz) of the light grey to do the underside of the plane and the pylons but only about 3oz to do the top of the plane. I was going for a really lightweight paint job so I was putting the paint on very carefully. It is a bit thin in a couple of places so I will have to touch it up a bit.
Sunday morning I reassembled the plane and went flying at my home field, the Sun Valley Fliers, on the north side of Phoenix. The take off runs at the lakebed were quite long (approx 700 ft) and the last time at the lake bed, I had six take off attempts but only 3 takeoffs so I was quite concerned that the plane wouldn't take off in time (700 ft runway at SVF) and I would go into the overrun. As such, I turned up the canards and elevators a bit. I had also fitted the custom main wheels and tires from Thomas White which have very low rolling resistance. In a pre-flight meeting with Tony Quist and Brian O'Meara (who was also present at the lake bed for the maiden and 2nd flight), we decided that the take off technique would be to hold full up elevator (like a Bandit), advance throttle to full to get the plane up to speed quickly then pull the throttle back to 2/3, watch for the nose to get light, ease out of elevator and flip to fly mode and HOPEFULLY, the plane would lift off nice and gentle. That was the plan.
Well, the plane accelerated rapidly (awesome power in the K210) into the 8 kt headwind and (it was later reported) was light on the nose in less than 200 feet. I certainly wasn't expecting that and wasn't even looking for it. I had the power back to 2/3 by this point and the plane rotated in front of us (~300 ft) and did the Gripen leap. I was so surprised that it took a few seconds to flip the switch to fly mode, get the plane leveled, and advance the throttle and by that time the plane lost 10-20 ft of altitude. The power kicked in and all was fine. I was back to 2/3 throttle by the time I turned downwind.
Essentially all of the flight was between 1/2 and 2/3 throttle with the exception of a big Split-S where I went to full power for the climb. The plane flies well and has great presence in the air. Here are a few flight shots. The right main landing gear door was held open by the airstream (at least at the beginning of the flight) but eventually closed. I'll keep an eye on that to see if I need to upsize the cylinder. The retract hydraulic system seemed to have no problems lifting the heavier scale tires.
The landing approach was done without the speedbrakes. I was hesitant to pull the power back too much and the first approach was too high so I went around and reduced the power to a lower setting for the next approach. I misjudged the approach a bit and was lined up to land off the far side of the runway so I tried to hold the plane off the ground with the nose high and add a bit of power to float it over the asphalt. The plane really was a floater and was flying quite slowly but I didn't add quite enough power and it touched down just beyond the edge of the runway and rolled onto the asphalt. OK, I'll take that.
I inspected the gear and found a crack in the wood mount for the left drag link trunion that was quickly fixed with Hysol. The E-clip had popped off the right drag link trunion and I didn't have a spare so I was done for the day. :-( On the way home, I went by ACE Hardware and picked up some 5mm E-clips so the plane is good to go for the next day of flying. In the mean time, I added some more scale details to the plane (taxi light on the forward nose door, and an exhaust duct in a cutout on the bottom of the plane).
Regards,
Jim
P.S.: Many thanks to Tony Quist and Brian O'Meara for their council and to Uncle Joe Balabon for the flight photos.
Last edited by rcjets_63; 04-13-2015 at 12:43 PM.
04-13-2015, 05:11 PM
#1229
Airplane getting some colors now - much better! Looking like an airplane now. 
Regarding the takeoffs, not being very familiar with the Gripen, I wonder if something can be done with a gyro on the canard surface, such that a small incidence angle exists on takeoff... Then as the aircraft increases AOA, the gyro kicks in to reduce angle of incidence... Atleast until you get to the point when you're gear up and are in "flight mode"... Just throwing out ideas. Don't try it before the contest! 
Seems like a nice platform though, to experiment with.
Regarding the takeoffs, not being very familiar with the Gripen, I wonder if something can be done with a gyro on the canard surface, such that a small incidence angle exists on takeoff... Then as the aircraft increases AOA, the gyro kicks in to reduce angle of incidence... Atleast until you get to the point when you're gear up and are in "flight mode"... Just throwing out ideas. Don't try it before the contest! Seems like a nice platform though, to experiment with.
04-14-2015, 09:53 AM
#1230
Thanks for the suggestions....The basic issue is that you need a lot of up elevator and up canard to get the plane to start to rotate. Once the nose is at a minor AOA, it begins to "kite" and develop lift. At that point, you need a lot less up elevator and neutral or even slightly negative canard. It is possible to do this manually (There is a video of Janne doing five nice takeoffs on YouTube). This may just be a matter of finding the right power setting and elevator setting. We'll see. As a backup plan, I can install a second Cortex just to control the canards.
My 1/5 scale Euro jet pilot from Tailored Pilots was sitting quietly by the door when I arrived home last night. I put "Roman" in the cockpit and he made himself right at home and fit perfectly. Wilson Li at Tailored Pilots did a fantastic job including the custom name tag and badges on the flight suit (which is indeed green - it looks brownish in the photos for some reason).
I finished the body filler work last night so the inlets nicely blend into the fuselage. With that done, I finished painting the underside of the nose. Next up tonight is completing the painting of the upper fuselage/nose section. Attached is a pic showing the location of the upper/lower color transition line.
Regards,
Jim
My 1/5 scale Euro jet pilot from Tailored Pilots was sitting quietly by the door when I arrived home last night. I put "Roman" in the cockpit and he made himself right at home and fit perfectly. Wilson Li at Tailored Pilots did a fantastic job including the custom name tag and badges on the flight suit (which is indeed green - it looks brownish in the photos for some reason).
I finished the body filler work last night so the inlets nicely blend into the fuselage. With that done, I finished painting the underside of the nose. Next up tonight is completing the painting of the upper fuselage/nose section. Attached is a pic showing the location of the upper/lower color transition line.
Regards,
Jim
Last edited by rcjets_63; 04-14-2015 at 09:56 AM.
04-14-2015, 11:57 AM
#1232
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Jim,
Just my opinion, but, pulling back to less than full throttle on takeoff seems to be a recipe for unnecessary drama, if not disaster! If you let off some up elevator input as soon as you see the nose lighten, you can still make a smooth transition. You can reduce throttle as soon as the gear is up.
My understanding is that as soon as you have a positive AOA, if you release all elevator input the gyro should maintain that AOA, making for a very smooth transition.
Congrats on the successful flights! She's looking good!
David S
Just my opinion, but, pulling back to less than full throttle on takeoff seems to be a recipe for unnecessary drama, if not disaster! If you let off some up elevator input as soon as you see the nose lighten, you can still make a smooth transition. You can reduce throttle as soon as the gear is up.
My understanding is that as soon as you have a positive AOA, if you release all elevator input the gyro should maintain that AOA, making for a very smooth transition.
Congrats on the successful flights! She's looking good!
David S
04-14-2015, 01:10 PM
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Jim,
Note on my SM/Xtreme Gripen I restricted the canard throw to +5 degrees and zero down for the best takeoff and general handling characteristics. This minimal throw prevents nose tuck in the turns and virtually eliminates the "Gripen Leap". My Gripen is powered by a JC Rabbit, older version at 19 lbs thrust, and powers the model very well. You might want to try a takeoff flight mode with limited UP throw for takeoffs and extended throw for high alpha and other flight conditions. Good luck in all this.
Rgds,
Art
Note on my SM/Xtreme Gripen I restricted the canard throw to +5 degrees and zero down for the best takeoff and general handling characteristics. This minimal throw prevents nose tuck in the turns and virtually eliminates the "Gripen Leap". My Gripen is powered by a JC Rabbit, older version at 19 lbs thrust, and powers the model very well. You might want to try a takeoff flight mode with limited UP throw for takeoffs and extended throw for high alpha and other flight conditions. Good luck in all this.
Rgds,
Art
04-14-2015, 03:39 PM
#1235
Jim the jet looks grate ,I fix the takeoff on my skymaster gripen just by switching the front spring by harder and cuting by 1/4" the main springs and this fixed the jump takeoff problem at least by 50% and when I changed the main gear from 90 degre to 85 degre the helped so much I was able to make complet south take offs .
04-14-2015, 11:02 PM
#1236
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On my AW Gripen I take off on about 60-70% power(P-300)and I hold full elevator from the begining of the takeoff roll.I have lots of canard movment in takeoff mode,but I have about 80-90% expo so it is smooth in the middle and full movment only at the ends of the stick travel.
I also have the pitch gyro on the canard not on the elevator,the helps smooth out the takeoff,that work very well for my and I use a short runway.
Tom Storvik
I also have the pitch gyro on the canard not on the elevator,the helps smooth out the takeoff,that work very well for my and I use a short runway.
Tom Storvik
04-14-2015, 11:53 PM
#1237
Hi Tom,
Thanks for the post. Can you confirm the amount of elevator and canard travel you are using please? Are you switching to fly mode (no mixing of elevators->canards and elevators-> ailerons) when the plane gets light on the nose wheel or do you just ease off the elevator and the canards go to near neutral due to your expo setting?
Also, I noticed you mentioned having a P300 installed and using 70% power to take off. Janne Seppanen has a P200 and I have a K210 and we are both taking off at 70% power too. However, 70% of 300N is about 100% of 200N so it would appear that the throttle setting isn't all that critical. Have you any thoughts on this?
Jim
Thanks for the post. Can you confirm the amount of elevator and canard travel you are using please? Are you switching to fly mode (no mixing of elevators->canards and elevators-> ailerons) when the plane gets light on the nose wheel or do you just ease off the elevator and the canards go to near neutral due to your expo setting?
Also, I noticed you mentioned having a P300 installed and using 70% power to take off. Janne Seppanen has a P200 and I have a K210 and we are both taking off at 70% power too. However, 70% of 300N is about 100% of 200N so it would appear that the throttle setting isn't all that critical. Have you any thoughts on this?
Jim
Last edited by rcjets_63; 04-15-2015 at 07:43 AM.
04-15-2015, 08:31 AM
#1238
Thanks for the inputs, guys.
I'm going to take a slow and cautious approach to solving the Gripen Leap issue. This plane is quite an investment of both time and money and thus an incremental approach seems appropriate. My home field has a 700 foot runway and while the overshoot is not too bad, a setup (such as disabling the canards) which results in a failure to take-off, will put the plane into the overshoot and potentially result in damage. There are only two weeks to Top Gun and four months to the JWM so I'm not interested in taking any unnecessary risks.
It's really just a case of weighing the risks/rewards:
Risk: Put a $20,000 airplane (that has taken years to build and well over 1000 hours this year alone) into the overshoot, tear out the gear or having other damage causing me to miss Top Gun or the JWM.
Reward: Having the take-off score in the 9 - 9.5 range instead of the 6.5 - 7.5 range at Top Gun.
It should also be recognized that there are some major differences between the AW Gripen and smaller Gripens like the SM/Xtreme. JetLegend, and Paul Gray. The SM/Xtreme, the gear is not in the scale location....it was specifically moved forward 1-1/2" in order to help improve rotation. Other tricks to reduce the leap were extending the nose gear strut to establish a positive AOA but this compromises the scale fidelity of the model. The Paul Gray Gripen has even less scale fidelity than the SM. I've had two SM Gripens with over 300 flights, have a JL/GJC Gripen, and also a Paul Grey Gripen and these are different than the AW.
A gyro is an interesting idea, and it would likely dampen the leap, but the idea is to find the takeoff technique that results in a minimal leap and then add the gyro to smooth out that response.
In other news, had a bit of body filler work to do in the upper forward fuselage so I didn't get the painting done last night. However, while waiting for the filler/primer to dry, I whipped up a centerline pylon with a BVM EZ drop to carry one of the D4S drop tanks. Dropping ordnance/tanks is not only a lot of fun, but it is also scoring maneuver at Top Gun. Having the pylon & tank installed also really adds to the look of the plane. I'll post some pics of it installed later in the week and will do a flight testing/release this weekend. The pylon is 17-13/16" long with a 1 degree taper, has 1/8" thick balsa sides, plywood/basswood ribs, and balsa block leading and trailing edges.
Jim
I'm going to take a slow and cautious approach to solving the Gripen Leap issue. This plane is quite an investment of both time and money and thus an incremental approach seems appropriate. My home field has a 700 foot runway and while the overshoot is not too bad, a setup (such as disabling the canards) which results in a failure to take-off, will put the plane into the overshoot and potentially result in damage. There are only two weeks to Top Gun and four months to the JWM so I'm not interested in taking any unnecessary risks.
It's really just a case of weighing the risks/rewards:
Risk: Put a $20,000 airplane (that has taken years to build and well over 1000 hours this year alone) into the overshoot, tear out the gear or having other damage causing me to miss Top Gun or the JWM.
Reward: Having the take-off score in the 9 - 9.5 range instead of the 6.5 - 7.5 range at Top Gun.
It should also be recognized that there are some major differences between the AW Gripen and smaller Gripens like the SM/Xtreme. JetLegend, and Paul Gray. The SM/Xtreme, the gear is not in the scale location....it was specifically moved forward 1-1/2" in order to help improve rotation. Other tricks to reduce the leap were extending the nose gear strut to establish a positive AOA but this compromises the scale fidelity of the model. The Paul Gray Gripen has even less scale fidelity than the SM. I've had two SM Gripens with over 300 flights, have a JL/GJC Gripen, and also a Paul Grey Gripen and these are different than the AW.
A gyro is an interesting idea, and it would likely dampen the leap, but the idea is to find the takeoff technique that results in a minimal leap and then add the gyro to smooth out that response.
In other news, had a bit of body filler work to do in the upper forward fuselage so I didn't get the painting done last night. However, while waiting for the filler/primer to dry, I whipped up a centerline pylon with a BVM EZ drop to carry one of the D4S drop tanks. Dropping ordnance/tanks is not only a lot of fun, but it is also scoring maneuver at Top Gun. Having the pylon & tank installed also really adds to the look of the plane. I'll post some pics of it installed later in the week and will do a flight testing/release this weekend. The pylon is 17-13/16" long with a 1 degree taper, has 1/8" thick balsa sides, plywood/basswood ribs, and balsa block leading and trailing edges.
Jim
Last edited by rcjets_63; 04-15-2015 at 08:41 AM.
04-15-2015, 01:04 PM
#1239
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Hi Jim
I have my Gripen setup as a deltaving in the transmitter, I have not split it into elevator an aileron.I have also mix the canards with the elevator , on mode for takeoff/landing an on for normal flight.I use the gear switch too change between the modes.Since I have lots of expo in the takeoff/ landing mode it is no problem too fly with and you don't have no rush too switch over to the normal mode,than you can have focus on the takeoff.In normal mode I have very little travel on the canard.I can give you the travels for the rudders tomorrow.
On the powersettings for the takeoff I have about little over the half of the stick travel, maybe that's is about 50-60% power???
After I put in the Igyro in Gripen it became a total differnt plan,it fly so much smoother.If it is a plane that's need gyro,Gripen is the plan!
Tom
I have my Gripen setup as a deltaving in the transmitter, I have not split it into elevator an aileron.I have also mix the canards with the elevator , on mode for takeoff/landing an on for normal flight.I use the gear switch too change between the modes.Since I have lots of expo in the takeoff/ landing mode it is no problem too fly with and you don't have no rush too switch over to the normal mode,than you can have focus on the takeoff.In normal mode I have very little travel on the canard.I can give you the travels for the rudders tomorrow.
On the powersettings for the takeoff I have about little over the half of the stick travel, maybe that's is about 50-60% power???
After I put in the Igyro in Gripen it became a total differnt plan,it fly so much smoother.If it is a plane that's need gyro,Gripen is the plan!
Tom
04-15-2015, 01:04 PM
#1240
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Hi Jim
I have my Gripen setup as a deltaving in the transmitter, I have not split it into elevator an aileron.I have also mix the canards with the elevator , on mode for takeoff/landing an on for normal flight.I use the gear switch too change between the modes.Since I have lots of expo in the takeoff/ landing mode it is no problem too fly with and you don't have no rush too switch over to the normal mode,than you can have focus on the takeoff.In normal mode I have very little travel on the canard.I can give you the travels for the rudders tomorrow.
On the powersettings for the takeoff I have about little over the half of the stick travel, maybe that's is about 50-60% power???
After I put in the Igyro in Gripen it became a total differnt plan,it fly so much smoother.If it is a plane that's need gyro,Gripen is the plan!
Tom
I have my Gripen setup as a deltaving in the transmitter, I have not split it into elevator an aileron.I have also mix the canards with the elevator , on mode for takeoff/landing an on for normal flight.I use the gear switch too change between the modes.Since I have lots of expo in the takeoff/ landing mode it is no problem too fly with and you don't have no rush too switch over to the normal mode,than you can have focus on the takeoff.In normal mode I have very little travel on the canard.I can give you the travels for the rudders tomorrow.
On the powersettings for the takeoff I have about little over the half of the stick travel, maybe that's is about 50-60% power???
After I put in the Igyro in Gripen it became a total differnt plan,it fly so much smoother.If it is a plane that's need gyro,Gripen is the plan!
Tom
04-15-2015, 02:01 PM
#1241
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Jim,
At this stage I would proceed with extreme caution in regards to any AW Gripen mods. It is better to accept a several point downgrade at TG rather than risk the model.
I know that you have vast experience with the SM/Xtreme version and some of the suggestions do not apply to the larger AW model. Good luck in sorting this all out.
Rgds,
Art
At this stage I would proceed with extreme caution in regards to any AW Gripen mods. It is better to accept a several point downgrade at TG rather than risk the model.
I know that you have vast experience with the SM/Xtreme version and some of the suggestions do not apply to the larger AW model. Good luck in sorting this all out.
Rgds,
Art
04-15-2015, 03:35 PM
#1242
Thanks Art, slow and steady wins the race is what I'm going for. I will get this beast tamed!!!
I heard from Radek Suk in the Chzech Republic today. He has just test flown his second AW Gripen (his first was retired and is now on display at an airport). The new bird was done in the CzAF 2013 NATO Tiger Meet scheme and has electric retracts. The nose unit is off-the-shelf Electron 50 unit. The mains were made by a buddy of his using SAVOX servos (modified to remove the position feedback) to drive a screw mechanism.
Regards,
Jim
I heard from Radek Suk in the Chzech Republic today. He has just test flown his second AW Gripen (his first was retired and is now on display at an airport). The new bird was done in the CzAF 2013 NATO Tiger Meet scheme and has electric retracts. The nose unit is off-the-shelf Electron 50 unit. The mains were made by a buddy of his using SAVOX servos (modified to remove the position feedback) to drive a screw mechanism.
Regards,
Jim
04-16-2015, 11:02 AM
#1244
Sebastian, yeah, his is sitting with a nose up attitude. This is likely to reduce the leap and therefore receiving more points in the flying rounds, but comprimises the scale fidelity resulting in fewer points in static. Overall, it may be the best comprimise.
I managed to get the airframe painting done last night and was pleased with the overall look. The blend line between the upper/lower colors took a couple of attempts but it wasn't too hard as I have a bunch of photos of aircraft 9245 and the blend line passes near some panel lines/features (see photo with red circles) which made for a useful painting guide. I have a slight adjustment to make on the angle of the blend line forward of the AOA vane panel and up over the nose and another tweek near the formation lights.
The only remaining painting is the larger markings (national insignia, 9245, DANGER, etc) and a few scale details such as the gun and the ground terrain radar transmitter and receiver panels on the underside of the nose. This is detail work that will be done with my small Paasche airbrush. The gun discoloration looks similar to the hot section on an F-100 so I will use the BVM detail paint kit (which arrives Friday) to produce the effect.
The new vinyl covers for the canards and fin were printed by Bob Belluomini and arrive today. Bob owns a printing company and made the vinyls on his high end printing & laminating equipment and I'm positive that they will be "dead-on balls accurate" to the full scale.
I mounted the centerline pylon and drop tank last night and am very pleased with how it looks/fits. The pylon uses two 4-40 SHCS to mount into hard points I installed in the belly of the model. The rear end of the pylon extends over the engine hatch preventing the hatch from being removed when the pylon is installed. I'll put up with this for now but expect that I'll eventually cut off the aft end of the pylon and glue it to the engine hatch for ease of maintenance.
After that, it's just the dry transfers and weathering. I'm looking forward to trying some of the weatherin techniques that Sean McHale wrote about in the Oct/Nov 2014 issue of RCJI.
Eight days left until it gets loaded in the back of a trailer and heads to Top Gun. I'm told that I won't be the first guy or the last to show up at Top Gun with barely dry paint. At least I (probably) won't be painting it in the tents there. I may be weathering it though.
Regards,
Jim
I managed to get the airframe painting done last night and was pleased with the overall look. The blend line between the upper/lower colors took a couple of attempts but it wasn't too hard as I have a bunch of photos of aircraft 9245 and the blend line passes near some panel lines/features (see photo with red circles) which made for a useful painting guide. I have a slight adjustment to make on the angle of the blend line forward of the AOA vane panel and up over the nose and another tweek near the formation lights.
The only remaining painting is the larger markings (national insignia, 9245, DANGER, etc) and a few scale details such as the gun and the ground terrain radar transmitter and receiver panels on the underside of the nose. This is detail work that will be done with my small Paasche airbrush. The gun discoloration looks similar to the hot section on an F-100 so I will use the BVM detail paint kit (which arrives Friday) to produce the effect.
The new vinyl covers for the canards and fin were printed by Bob Belluomini and arrive today. Bob owns a printing company and made the vinyls on his high end printing & laminating equipment and I'm positive that they will be "dead-on balls accurate" to the full scale.
I mounted the centerline pylon and drop tank last night and am very pleased with how it looks/fits. The pylon uses two 4-40 SHCS to mount into hard points I installed in the belly of the model. The rear end of the pylon extends over the engine hatch preventing the hatch from being removed when the pylon is installed. I'll put up with this for now but expect that I'll eventually cut off the aft end of the pylon and glue it to the engine hatch for ease of maintenance.
After that, it's just the dry transfers and weathering. I'm looking forward to trying some of the weatherin techniques that Sean McHale wrote about in the Oct/Nov 2014 issue of RCJI.
Eight days left until it gets loaded in the back of a trailer and heads to Top Gun. I'm told that I won't be the first guy or the last to show up at Top Gun with barely dry paint. At least I (probably) won't be painting it in the tents there. I may be weathering it though.
Regards,
Jim
Last edited by rcjets_63; 04-16-2015 at 11:53 AM.
04-17-2015, 12:30 PM
#1247
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Join Date: May 2004
Location: Kungsbacka, SWEDEN
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Tom Storvik with his Gripen, Little old move but realy tight flightbox.
https://www.youtube.com/watch?v=d8zkK7HeFrE //
Jonas
https://www.youtube.com/watch?v=d8zkK7HeFrE //
Jonas
04-18-2015, 08:36 AM
#1248
After spending the week painting, I went out for some fresh air and got some more Gripen flights in yesterday. I even remembered to bring my video camera to the field. One of the club members kindly shot the video which I uploaded to YouTube. Raw footage, sorry, didn't have time to do any editing.
This was flight number eight, and the third off of asphalt. There was a definite reduction in the "Gripen Leap" which is encouraging. Based on the experience gained in the previous flights off an asphalt runway, I had a very good idea of when/where the plane would get light on the nose wheel. I stood in an ideal location to see it clearly and was ready with my finger on the flight mode switch. I applied ~70% power (you can hear the radio beep as the throttle goes through the 1/2 way point) and held full up elevator. When the plane got light on the nose, I switched mode but kept the full up elevator and it lifted off. The takeoff was still a bit steep, so on the next flight, I'll relax the up elevator just a bit after I see the nose rise. There was also a bit of pitch oscillation in the climbout so a bit more expo (I believe I'm using 30% now) will be added. Still, it was a vast improvement over my previous flights and this is encouraging and gave me a big smile.
The flight was mostly a few simple practice maneuvers for Top Gun (high speed pass, low speed pass, roll, etc) but also I tested the speed brakes in flight. They didn't open due to minimal/zero gap around the speed brake and a bit of play in the hinge. While they work great on the ground, the drag and air cylinder pushes the speed brakes rearwards just enough that the back edge jams against the cutout. I'll sand 1/32" or so off the back edge of the speedbrakes and try again tomorrow.
I also did a drop test of the centerline tank. While the tank did eventually drop, it held on too long so I'll have to sort that out too. I'm not sure at this point if it is an aerodynamic or mechanical problem.
Here's the video....
https://www.youtube.com/watch?v=GtXRUNV1JJ0&feature=youtu.be Regards,
Jim
This was flight number eight, and the third off of asphalt. There was a definite reduction in the "Gripen Leap" which is encouraging. Based on the experience gained in the previous flights off an asphalt runway, I had a very good idea of when/where the plane would get light on the nose wheel. I stood in an ideal location to see it clearly and was ready with my finger on the flight mode switch. I applied ~70% power (you can hear the radio beep as the throttle goes through the 1/2 way point) and held full up elevator. When the plane got light on the nose, I switched mode but kept the full up elevator and it lifted off. The takeoff was still a bit steep, so on the next flight, I'll relax the up elevator just a bit after I see the nose rise. There was also a bit of pitch oscillation in the climbout so a bit more expo (I believe I'm using 30% now) will be added. Still, it was a vast improvement over my previous flights and this is encouraging and gave me a big smile.
The flight was mostly a few simple practice maneuvers for Top Gun (high speed pass, low speed pass, roll, etc) but also I tested the speed brakes in flight. They didn't open due to minimal/zero gap around the speed brake and a bit of play in the hinge. While they work great on the ground, the drag and air cylinder pushes the speed brakes rearwards just enough that the back edge jams against the cutout. I'll sand 1/32" or so off the back edge of the speedbrakes and try again tomorrow.
I also did a drop test of the centerline tank. While the tank did eventually drop, it held on too long so I'll have to sort that out too. I'm not sure at this point if it is an aerodynamic or mechanical problem.
Here's the video....
https://www.youtube.com/watch?v=GtXRUNV1JJ0&feature=youtu.be Regards,
Jim
