Help on building a Jetlegend Gripen
11-07-2006, 01:27 AM
#1
Help on building a Jetlegend Gripen
I Have a kit of the early Jetlegend gripen for which I only have the plans. Does any body know about any manual that includes a building secuence for this airplane? Was there supposed to be a manual included with the kit? Has any body written instructuctions for this airplane? I bought my kit through rcuniverse marketplace and there was none in the box. Any help will be appreciated.
Kind regards,
Jose E. Lopez
Kind regards,
Jose E. Lopez
11-07-2006, 06:53 AM
#3
RE: Help on building a Jetlegend Gripen
This link to the Skymaster Grippen shows some instructions. As far as I know the Skymaster & the Jet Legend Grippen are the same.
http://www.skymasterjet.com/arf39.htm
Regards
Jim
http://www.skymasterjet.com/arf39.htm
Regards
Jim
11-07-2006, 05:11 PM
#4
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RE: Help on building a Jetlegend Gripen
Jose,
Just follow the directions on Skymaster's website. The older SM Gripen and the JL Gripen are identical.
I have built both the original SM Gripen and the SM ARF+ Gripen. PM me if you have any questions. I do recommend that you add a small piece of plywood underneath the rear of the turbine mount rails to support them and tie the load into the fuselage. Several people have had the mounts come loose on a hard landing and this will fix that. Attached are a couple of pictures.
Joe
Just follow the directions on Skymaster's website. The older SM Gripen and the JL Gripen are identical.
I have built both the original SM Gripen and the SM ARF+ Gripen. PM me if you have any questions. I do recommend that you add a small piece of plywood underneath the rear of the turbine mount rails to support them and tie the load into the fuselage. Several people have had the mounts come loose on a hard landing and this will fix that. Attached are a couple of pictures.
Joe
11-08-2006, 05:29 AM
#6
RE: Help on building a Jetlegend Gripen
Ok Joe thanks for the advise. I Had read some posts about this issue and had plans to do something about. Your solution to it seems very appropriate.
With regards to assembling the kit, my main issue is that there are no references inside the fuselage as to where to glue the formers. It would have been of help if there were some marks as to where to glue them in place correctly.
It is probably a good approach to define a reference in the fuselage, take measurements in the plan using the same reference, and define location for each former. Once found former "should be" position, drill small holes that would allow usage of toothpicks or something that would help assure former is being glued in the right place. I Would like to hear comments on some other method to go about this.
Jeff, as you may see this is a kit and not the ARF version.
Jim, thanks for you suggestion. I can probably make good use of the information in the ARF instructions to guide myself in the placement of accesories, batt, uat etc inside the airframe.
regards,
Jose
With regards to assembling the kit, my main issue is that there are no references inside the fuselage as to where to glue the formers. It would have been of help if there were some marks as to where to glue them in place correctly.
It is probably a good approach to define a reference in the fuselage, take measurements in the plan using the same reference, and define location for each former. Once found former "should be" position, drill small holes that would allow usage of toothpicks or something that would help assure former is being glued in the right place. I Would like to hear comments on some other method to go about this.
Jeff, as you may see this is a kit and not the ARF version.
Jim, thanks for you suggestion. I can probably make good use of the information in the ARF instructions to guide myself in the placement of accesories, batt, uat etc inside the airframe.
regards,
Jose
11-08-2006, 05:39 AM
#7
RE: Help on building a Jetlegend Gripen
Jose. Jet Legend supply a full size plan with their kits. This explains fitting everything.
Yang at JL is very helpful. I am sure if you e-mailed him, he would send you a plan. If not, maybe Jeff Sewell can help you out with a copy.
Regards
Jim
Yang at JL is very helpful. I am sure if you e-mailed him, he would send you a plan. If not, maybe Jeff Sewell can help you out with a copy.
Regards
Jim
11-08-2006, 09:13 AM
#10
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RE: Help on building a Jetlegend Gripen
I think a good approach would be to take the plans and mark the location of every former exactly before beginning anything. Maybe you can take a string and stretch it from the end of the tailcone on the plan to where the former goes, and then mark it on the bottom of the fuse. Most of the horizontal formers, like the LG mounts, engine mounts, radio trays, they all probably key into the horizontal formers, placing them should be no trouble. You can use a level to make sure the formers are square while they are drying.
Dry fit everything first. Usually, formers will require some sort of sanding to fit properly, I guess glasswork is not always identical. You don't want to find a former fits too tightly when you already have glue on it! Also be sure to rough up the area where the formers go inside. And be aware that some things might be subassemblies that need to be built before they go into the fuse.
Fitting the wings and wing spar holders is another issue. If you can put them in afterwards, that might be easier, doing the wings at the same time as the formers sounds better, but you need to be very aware of where those formers are, and where the wing spars are, before gluing.
I would do the whole thing in one evening, with Hysol, which is the strongest, and gives plenty of time to adjust things while drying. I would just think through the wing (and canard) attachments before beginning, and make sure my bench is prepared to jig everything up in the right places before beginning, and then I would do everything at once.
A great craftsman once told me that preparing the tools for the job is 85% of the job, actually DOING the job is the easy part.
I have not built a JL Gripen, but I have built lots of other glass jets, and found this is the best way for me. Hope it helps somewhat.
Dry fit everything first. Usually, formers will require some sort of sanding to fit properly, I guess glasswork is not always identical. You don't want to find a former fits too tightly when you already have glue on it! Also be sure to rough up the area where the formers go inside. And be aware that some things might be subassemblies that need to be built before they go into the fuse.
Fitting the wings and wing spar holders is another issue. If you can put them in afterwards, that might be easier, doing the wings at the same time as the formers sounds better, but you need to be very aware of where those formers are, and where the wing spars are, before gluing.
I would do the whole thing in one evening, with Hysol, which is the strongest, and gives plenty of time to adjust things while drying. I would just think through the wing (and canard) attachments before beginning, and make sure my bench is prepared to jig everything up in the right places before beginning, and then I would do everything at once.
A great craftsman once told me that preparing the tools for the job is 85% of the job, actually DOING the job is the easy part.
I have not built a JL Gripen, but I have built lots of other glass jets, and found this is the best way for me. Hope it helps somewhat.
11-08-2006, 09:33 AM
#11
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RE: Help on building a Jetlegend Gripen
yes - it flies great - the high alpha slow flight with cannards is absolutely amazing and this jet flies beyond our highest expectations - there was a lot of negetive stuff written but its mostly bang!! its all in the set up - it lands like a baby as well. we have 4 grippens in our group with 2 already flying and 1 more in progress.
11-08-2006, 09:43 AM
#12
RE: Help on building a Jetlegend Gripen
Easytiger, thanks for taking the time to write in such detail. Great piece of advice you have written.
Adrian, can you throw in some info on your settings? Would like to hear about your findings.
Regards, Jose
Adrian, can you throw in some info on your settings? Would like to hear about your findings.
Regards, Jose
11-08-2006, 09:51 AM
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RE: Help on building a Jetlegend Gripen
Jose
ET is not here just to kick ass! I can see a new career for him writing manuals, his style is easy to read and covers all the important details, his reviews in RCJI are also informative and good reading.
BTW I also reserve the right to disagree with him when required [:@]
John
ET is not here just to kick ass! I can see a new career for him writing manuals, his style is easy to read and covers all the important details, his reviews in RCJI are also informative and good reading.
BTW I also reserve the right to disagree with him when required [:@]
John
11-08-2006, 10:04 AM
#14
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RE: Help on building a Jetlegend Gripen
Goshers! Where's the "blushing" smiley?
I'm doing another one now.
"Career?" That implies I might actually be making some money! Ha!
The RCJI articles are fun to do, but it's a lot of work, too.
Should I do one for the Gripen? The only problem is, I don't really LIKE the Gripen that much, and there are other subjects I would rather do first.
I'm doing another one now.
"Career?" That implies I might actually be making some money! Ha!
The RCJI articles are fun to do, but it's a lot of work, too.
Should I do one for the Gripen? The only problem is, I don't really LIKE the Gripen that much, and there are other subjects I would rather do first.
11-08-2006, 07:14 PM
#15
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RE: Help on building a Jetlegend Gripen
Jose,
Here's another build suggestion. Throw away the retract plates and make new ones out of good quality aircraft grade plywood. The supplied Chinese plywood is not very strong.
My main gear plates broke easily. I made new ones out of 1/4" plywood and they were much stronger. This was a weak point on early Gripens. Their fix, to add small vertical pieces on top of the horizontal plates (see second picture in post #8), does not add much to the strength. The original plates were 5 mm. cheap grade plywood. 1/4 inch is about 8 mm. Also I prefer to use blind T-nuts to attach retracts. This way you don't need the small vertical pieces and you have room for T-nuts.
Joe
Here's another build suggestion. Throw away the retract plates and make new ones out of good quality aircraft grade plywood. The supplied Chinese plywood is not very strong.
My main gear plates broke easily. I made new ones out of 1/4" plywood and they were much stronger. This was a weak point on early Gripens. Their fix, to add small vertical pieces on top of the horizontal plates (see second picture in post #8), does not add much to the strength. The original plates were 5 mm. cheap grade plywood. 1/4 inch is about 8 mm. Also I prefer to use blind T-nuts to attach retracts. This way you don't need the small vertical pieces and you have room for T-nuts.
Joe
11-11-2006, 06:03 PM
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RE: Help on building a Jetlegend Gripen
ORIGINAL: adrian-RCU
yes - it flies great - the high alpha slow flight with cannards is absolutely amazing and this jet flies beyond our highest expectations - there was a lot of negetive stuff written but its mostly bang!! its all in the set up - it lands like a baby as well. we have 4 grippens in our group with 2 already flying and 1 more in progress.
yes - it flies great - the high alpha slow flight with cannards is absolutely amazing and this jet flies beyond our highest expectations - there was a lot of negetive stuff written but its mostly bang!! its all in the set up - it lands like a baby as well. we have 4 grippens in our group with 2 already flying and 1 more in progress.
Adian,
what is your setup on your high alpha slow flight, can you give example of power, throw on each surface and input.
Thanks so much.
11-11-2006, 10:33 PM
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RE: Help on building a Jetlegend Gripen
a while back I started a thread on rcjet.net about building gripen. the landing gear supports were reinforced by me with carbon fiber. I have since ripped out most of plywood and placed aluminum brackets around mounts, similar to bvm's rafale.
here is thread. I will update it soon
http://www.rcjet.net/forum/showthread.php?t=1104
here is thread. I will update it soon
http://www.rcjet.net/forum/showthread.php?t=1104
11-12-2006, 12:37 PM
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RE: Help on building a Jetlegend Gripen
ORIGINAL: dragonpilot
Adian,
what is your setup on your high alpha slow flight, can you give example of power, throw on each surface and input.
Thanks so much.
ORIGINAL: adrian-RCU
yes - it flies great - the high alpha slow flight with cannards is absolutely amazing and this jet flies beyond our highest expectations - there was a lot of negetive stuff written but its mostly bang!! its all in the set up - it lands like a baby as well. we have 4 grippens in our group with 2 already flying and 1 more in progress.
yes - it flies great - the high alpha slow flight with cannards is absolutely amazing and this jet flies beyond our highest expectations - there was a lot of negetive stuff written but its mostly bang!! its all in the set up - it lands like a baby as well. we have 4 grippens in our group with 2 already flying and 1 more in progress.
Adian,
what is your setup on your high alpha slow flight, can you give example of power, throw on each surface and input.
Thanks so much.
11-12-2006, 09:17 PM
#20
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RE: Help on building a Jetlegend Gripen
Nice, thanks for your reply and throws,
my good friend maidened my SM Gripen, I believe he used low rate canards and middle rate elevons the whole time, we'll experient more soon. I have it setup with triple rates for canard, off, low and high. He wasn't used to this airframe and hadn't flown in 6 months, what a friend I am, here maiden my jet....
Here is the landing, actually hit the tail cone first, causing it to bounce..
http://www.rcmachinery.com/gripenlanding.wmv
my good friend maidened my SM Gripen, I believe he used low rate canards and middle rate elevons the whole time, we'll experient more soon. I have it setup with triple rates for canard, off, low and high. He wasn't used to this airframe and hadn't flown in 6 months, what a friend I am, here maiden my jet....
Here is the landing, actually hit the tail cone first, causing it to bounce..
http://www.rcmachinery.com/gripenlanding.wmv
11-13-2006, 03:37 AM
#21
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RE: Help on building a Jetlegend Gripen
ooops - no problem it will get only better - i have learnt that because its a delta you just let it wash in - hope all is ok[8D]
- no problem it will get only better - i have learnt that because its a delta you just let it wash in - hope all is ok[8D]
11-18-2006, 04:03 AM
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RE: Help on building a Jetlegend Gripen
engine is a 12 kg model mechanics and the CG is spec - 1/2 inch or 1.5 cm back - test flight was on forward spec but it was a little nose heavy - now much better a little back. all up weight is 11kg full
