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2019 Fantasy Aircraft Design & Build Challenge! CoD Infinite Warfare Jackal Space fighter

JTarmstr

Well-known member
#42
Looking really nice @JTarmstr! Do you have a weighing scales? Would be useful for checking the all up weight and static thrust before chucking her into the blue yonder.

DamoRC
I weighed it in at 750 grams without battery, 935 with battery, while it isn't a 1:1 ratio it should be able to get into the air and if it doesnt I have 2 extra EDFs so I will double up.

Looking Good!

Hey, I recognize those servos! (I bought a pack of 10 too!) :LOL:
I bought 20 of them now I dont know what to do with them xD, they are so big!
 

JTarmstr

Well-known member
#44
I KNOW Right?!! :ROFLMAO:

I haven't even played with them yet, I think I'll put some in my edge if they are fast/responsive enough... REALLY curious to hear how they work out on your build!
I tested them, they are a bit slower than Ft Servos but they seem to have some major torque to them, I will hopefully record the maiden of the airplane and they are the most crucial part so we shall see.
 

DamoRC

Well-known member
Mentor
#45
I weighed it in at 750 grams without battery, 935 with battery, while it isn't a 1:1 ratio it should be able to get into the air and if it doesnt I have 2 extra EDFs so I will double up.
And the static thrust? It is worth checking this once your ESC is in. Although the EDFs will come with some verbiage around what thrust they produce or what size plane they can fly, each installation can be different and yours certainly is unique. So if you can, confirm what actual static thrust you are getting. Agreed, 1:1 is not necessary to fly but the more you have the better.

DamoRC
 

JTarmstr

Well-known member
#46
And the static thrust? It is worth checking this once your ESC is in. Although the EDFs will come with some verbiage around what thrust they produce or what size plane they can fly, each installation can be different and yours certainly is unique. So if you can, confirm what actual static thrust you are getting. Agreed, 1:1 is not necessary to fly but the more you have the better.

DamoRC
I dont have any way to measure static thrust. I was going to take it to a really long rarely used road and do some hi speed taxi tests but I would kind of rather it suffer a glorious demise instead of being replaced by a more efficient design.
 

DamoRC

Well-known member
Mentor
#49
I dont have any way to measure static thrust. I was going to take it to a really long rarely used road and do some hi speed taxi tests but I would kind of rather it suffer a glorious demise instead of being replaced by a more efficient design.
Based on the fact that you provided weights, I thought you have a scale. Then its just a matter of standing the model on its nose on the scale (even if you are holding it to keep it vertical) and give it 100% throttle. It might not be the most accurate but it will give you some idea.

Either way - best of luck!

DamoRC
 

JTarmstr

Well-known member
#51
Update:

I tested it, and it was really tail heavy, I didnt record it because I was just going to powered glide across my yard. Anyway it seems underpowered and tail heavy but once I balanced it seemed to fly ok albeit it couldn't sustain level flight. I think I will try one more time and then take a few weeks break, than build a dual EDF model.
 

kilroy07

Well-known member
#52
it seemed to fly ok albeit it couldn't sustain level flight.
3 or 4 cell?

Maybe the extra umph of a 4S will help...
I notice quite a bit of difference between my Viggen (3S) and Falcon/Viper (4S) and I don't think it has much to do with the 5mm of difference in the EDF (that said make sure your EDF can handle 4S.)
 

JTarmstr

Well-known member
#53
3 or 4 cell?

Maybe the extra umph of a 4S will help...
I notice quite a bit of difference between my Viggen (3S) and Falcon/Viper (4S) and I don't think it has much to do with the 5mm of difference in the EDF (that said make sure your EDF can handle 4S.)
Yeah, it was 3s, the problem is that its not recommended for me to use a 4s on the EDF and even if it was, I could spend $20 dollars on a 4s but then i am not guaranteed that it would work. if it didnt work I would be down $20 dollars and potentially a EDF. I think its better I spend the money on a second ESC and rebuild it in a few weeks, the design seems promising, I also designed a FT style airfoil. I am also laying claim to first one to get in the air... for 10 seconds :p.
 

JTarmstr

Well-known member
#54
So I tried again and the crash was of epic proportions, unfortunately my photographer did capture it on film so all I have is a still of the aftermath.
Jackal crash.JPG


R.I.P. It was extremely tailheavy and just went straight vertical and then stalled at about 20 feet altitude. think I will take a break now and slowly rebuild the airplane. I do have a video of a earlier test which I will add. I cant really understand what was wrong with the CG, I made it extremely nose heavy and it still wanted to go upward, I think it might be the lifting body but I am not sure, I will have to explorewith glide tests a bit more.
 

rockyboy

Skill Collector
Mentor
#55
If it was nose heavy and still wanted to go vertical under power, I'd suggest it's a thrust angle problem.

It took me 3 tries with my Whatchamacallit flying wing to get enough thrust angle so it would go forward under power, and not into crazy never ending loops. But the CG was good from the beginning, and I could do a beautiful deadstick landing every time while I kept adding washers for thrust angle :D
 

JTarmstr

Well-known member
#56
If it was nose heavy and still wanted to go vertical under power, I'd suggest it's a thrust angle problem.

It took me 3 tries with my Whatchamacallit flying wing to get enough thrust angle so it would go forward under power, and not into crazy never ending loops. But the CG was good from the beginning, and I could do a beautiful deadstick landing every time while I kept adding washers for thrust angle :D
That makes sense since it glided ok for a plane with small wing area. I will have the video on youtube soon so maybe it will be easier to tell.
 

JTarmstr

Well-known member
#57
So, i haven't had much time to work on this, but i have been thinking more and i think i am going to do a major change with this. FT 22 style with an old C pack motor that i have, this should make getting a good CG easier and also if it crashes i am not down a weeks worth of building and 10 dollars. I have some technical drawings i made and will upload those at some point. The reason i am doing this is because the EDFs i got wont work well for this build (not enough power) and i dont like the idea of setting it up with dual or quadruple EDFs. Hopefully with the new set up idea I can make something that will be easy to build and fun to fly.
 

JTarmstr

Well-known member
#59
So i made a very embarrassing mistake, when i built the prototype i scaled the main fuselage from 10 inches to 12 inches. however i somehow forgot i did that and mounted the motor in the middle at 5 inches. that completely threw off the build and its so messed up it has to be scrapped. Anyway, i have started again, and i am quite determined to do all the measurements correctly this time.
P1200183.JPG