Hey Steve,
I will be just doing a sanding of the printed parts with no additional paint. I have one in black and one in white. Just basic gap filling with ABS slurry where its needed, and then matte or satin clear coats to seal in the vinyl and make it easier to wipe down from grass or dirt stains.
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Merry Christmas all!
Finally got around to another round of tests with 100% FSA exhaust and enlarged intake cheater. Overall, improvements were relatively minor, with 600g of thrust at 618W compared to 590g at 596W. 10 grams of increased thrust with the changes.
Earlier this week I quickly went out to confirm ease to hand-toss. below is a short video from the first of the 2 flights. I forgot to write down notes from the maiden, so I was re-learning a bit with what rates I had set for ailerons, rudder, and elevator. The plane felt a bit snappier than before when banking using ailerons with a bit of rudder, so I brought it down pretty quickly in the video. Besides, this, the plane takes off from an underhand toss pretty easily.
I have graphics coming in from Callie in the next week or 2, so I will have some photos to share of a completed U-2R and ER-2. I'm also going to try and vacuum from canopies for both airframes. Ordering some 1300mAH 4S packs as well.
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Files are now available on Cults3D.
There is a link in the description to a free test file/assembly manual.
https://cults3d.com/en/3d-model/game...627mm-wingspan
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That is amazing. I'm looking forward to printing up a handful of designs I have done on Solidworks. Formlabs Form 3 SLA printer is on its way to replace the Form 1+ I've had for the last 4 years...Leave a comment:
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The 70C 1000mAH pack was the only one that fit the battery compartment that RCJetwerx carried. I wanted the 1300mAH 45C pack, but it's dimension was 29mm x 34mm so too tall. The EDF pulls almost 40A, so 40C is really all that is needed.
speaking of weight reduction, I stumbled on a filament that is carbon impregnated and has a mass density that is ~20% lighter than ABS. So i can possibly lose almost 138g from the airframe if the filament works. this would get be sub 1kg AUW even with a 1300-1400mAH pack.Leave a comment:
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I also vote for option 2. Or option 3, any option that removes all unnecessary weight/lead from the airframe and increases battery capacity is a win win. I say option 3 due to the fact that it sounds like you can move both the battery and edf if needed to obtain proper cg without added any lead weight. Those batteries options I sent you would all be options with your new battery positions, but they were all 40c or 30c rated packs. I see in your pic your running a 70c pack, is that amount of C rating necessary for your power system?Leave a comment:
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Thanks Phantom . Ill give those a look. I had a sudden moment of realization this morning that the last flight of the day I came down with 60% for 2:30 duration, and that pack I kept warm inside my jacket. So my first flight times were on cold batteries which affects performance.
I also removed the mobius camera from the tail, and the 14g of lead nose ballast to see where my packs need to be to hit CG without any video recording. I realized that the battery needs to be mounted much further back in the canopy compartment.
I now have 2 options to take:- keep the current battery mounting configuration, but shift the EDF mounting further back to compensate without adding tail lead ballast
- battery size restriction will remain the same with width and height
- Keep the current EDF location, and shift the battery to inside the canopy compartment.
- receiver will be shifted forward into the nose. or hidden slightly inaccessible under the servos.
- Size restriction will be increased to 32 w x 35 h
The flight was definitely pitchy due to being slightly tail heavy. The last 3 flights were better after I shifted the battery forward and got the elevator properly trimmed.Leave a comment:
- keep the current battery mounting configuration, but shift the EDF mounting further back to compensate without adding tail lead ballast
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DD,Thanks all!
Thanks! Always feels great when a scratchbuilt or printed model successfully flies and lands in one piece.
For the dolly, no physical changes were made, but I changed the placement of the airframe so that the CG was just slightly ahead of the rear axle on the dolly. There was still a tendency to weather-vane due to the 90 degree 10mph crosswinds but there was much more thrust to get it up to speed and airborne quicker. adding 50% differential to the ailerons also seems to help.
Maiden video below. 4S was able to give me 590g of thrust at ~596W. I am modifying the cheater intake to be slightly larger since I noticed the fan was sucking in through the nosecone and canopy cracks. flights ranged between 2:40-3:15 on the 1000mAH packs to 30% capacity, but removing the onboard camera and better throttle management should get me to the 3.5-4 minute range. I am limited to a size constraint of 35mm x 27mm for batteries, so it seems difficult to find any 1300-1600 4S packs. The only one I found was a 1400mAH turnigy pack so I might pick one up to try.
(edit) looks like BuddyRC carries 1300 glacier packs that are 33x26.
Check out these batteries from CHNL, fast shipping, reasonably priced, and they make up about 25% of my battery inventory and I've never had a cell drop, arrived dead, or failure. Most of the list is under your 27×35 requirement, however others are just over. All are 4s and 40c to 30c, due to you powering an edf, but if your setup can use a lower C rating, then you can get higher mah packs in 4s.
I think I have a little more room in my old phase 3 U-2 than you do in the battery bay...
Nice maiden, although it seemed a bit touchy on the pitch axis... sometimes on mine the elevator is so tiny I feel like I run out of authority if I get to slow.
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Thanks all!
Thanks! Always feels great when a scratchbuilt or printed model successfully flies and lands in one piece.
For the dolly, no physical changes were made, but I changed the placement of the airframe so that the CG was just slightly ahead of the rear axle on the dolly. There was still a tendency to weather-vane due to the 90 degree 10mph crosswinds but there was much more thrust to get it up to speed and airborne quicker. adding 50% differential to the ailerons also seems to help.
Maiden video below. 4S was able to give me 590g of thrust at ~596W. I am modifying the cheater intake to be slightly larger since I noticed the fan was sucking in through the nosecone and canopy cracks. flights ranged between 2:40-3:15 on the 1000mAH packs to 30% capacity, but removing the onboard camera and better throttle management should get me to the 3.5-4 minute range. I am limited to a size constraint of 35mm x 27mm for batteries, so it seems difficult to find any 1300-1600 4S packs. The only one I found was a 1400mAH turnigy pack so I might pick one up to try.
(edit) looks like BuddyRC carries 1300 glacier packs that are 33x26.
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Bravo Zulu, Dirty Dee! You should be very proud. I'm interested to see how your final dolly setup ended up being configured to give you a successful controlled launch.Leave a comment:
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