crayfellow
Member
I'd better start saving pennies, or maybe my kids will lend me some from their piggy banks
R&D Hex for Survey/Imaging/Conservation
- Thread starter crayfellow
- Start date
Mactadpole
Member
I figure your going to have somewhere between 600-800g more weight than what I have with the InfinityMR, GH4, and FPV equipment. What sort of landing gear are you thinking? Retractable will be more weight too.
I'll be fair and only add 700g to my model weight for a total model weight of 3200 g without Drive. Below is what you get with the KDE3520XF-400, 15" Tiger CF props, CC35A ESC's, and Tattu 16000mah battery. I don't know why you would need the 55A esc's since even at max its only hitting 24.56A. This puts you right at 49% throttle and about 14.5-17 minutes of flight time.
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I'll be fair and only add 700g to my model weight for a total model weight of 3200 g without Drive. Below is what you get with the KDE3520XF-400, 15" Tiger CF props, CC35A ESC's, and Tattu 16000mah battery. I don't know why you would need the 55A esc's since even at max its only hitting 24.56A. This puts you right at 49% throttle and about 14.5-17 minutes of flight time.
View attachment 24658
Attachments
crayfellow
Member
Wouldn't they be just about the same if you compare apples to apples (3rd axis for QuadFrame, but without the rotating legs), or no? It is possible the "custom" 24P InfinityMR motors are heavier, but I'm not sure that's the case. Other than that they are dimensionally similar.
crayfellow
Member
I have the QuadFrame light legs. Alternately if I use a QuadFrame gimbal, I would hope to use the fancy rotating legs, so similar weight there.
Yeah I know. I am going off of what KDE suggests.
In my fiddling I am using 3200g without drive in ecalc, just to standardize on your guess.
I have 1400g from @Motopreserve for the QuadFrame gimbal with legs. GH4+12mm is 569+260g. So we have 2229g between gimbal and camera.
QuadFrame says 880g for the foldable SIXcopter, so that gets us to 3109g. We're within the realm for sure, and you're right it's probably more.
Now I need to figure out if I can cram 15" prop into 795mm motor-to-motor distance (QuadFrame's spec for foldable SIX with 370mm arms), or get 400mm arms, or ...
Mactadpole
Member
I was able to find my spreadsheet for the build. I would go with these weights, most are from manufacturer but others I weighed myself. Some things there I have changed. I only have a 2-axis gimbal so going 3-axis will added a good bit more weight too. Keep in ming things like wire (=heavy) and copper PDB will add weight to all this. It is absolutely amazing how quickly you end up with an additional 500g or so when just changing/adding a few things (your camera alone is 453 g heavier than mine). For example, do the KDE motor weights given reflect the wire too? I would recommend to start a similar spreadsheet or a couple for alternate build directions. I would check into the rotating legs and how well they work with gimbal controllers. Seems I recall there being issues.
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crayfellow
Member
awesome, thanks! I do have spreadsheets but need to add weight.
Yeah, I have 315mm light legs as a backup so I could run it without the legs if necessary.
OK fellas so with 370mm arms we have 795mm (31.2992in) motor to motor. Is ~1.2" between props playing it too close and I *need* 400mm arms to run 15" props? I was only stuck on 14" based on their recommendation.
Motopreserve
Drone Enthusiast
1" between props should be fine. If you get more than 1/2" flex you have way bigger issues . Just make sure you check the center plates too.
The rotating landing gear issue is definitely with the Phobotic. The AM has been successfully integrated.
I have some KDE motors here for testing. I can weigh them and see how they compare to the KDE specs - to check if wires are included.
. Just make sure you check the center plates too.The rotating landing gear issue is definitely with the Phobotic. The AM has been successfully integrated.
I have some KDE motors here for testing. I can weigh them and see how they compare to the KDE specs - to check if wires are included.
crayfellow
Member
one dude on diydrones says:
"According to a white paper published by the University of Maryland Rotorcraft Engineering professor J. Gordon Leishman, two rotors overlapping by about 27% might be more efficient than if they were aerodynamically separated. It seems that the CH-47 series "Chinook" choppers have quite a good reputation for lifting capacity. In any event, the simple phenomenon of flow contraction might account for this apparent advantage. Suffices to say, from a pure thrust efficiency standpoint, you need not worry about too close unless the tips are hitting each other."
"According to a white paper published by the University of Maryland Rotorcraft Engineering professor J. Gordon Leishman, two rotors overlapping by about 27% might be more efficient than if they were aerodynamically separated. It seems that the CH-47 series "Chinook" choppers have quite a good reputation for lifting capacity. In any event, the simple phenomenon of flow contraction might account for this apparent advantage. Suffices to say, from a pure thrust efficiency standpoint, you need not worry about too close unless the tips are hitting each other."
crayfellow
Member
looking at my (unassembled) frame with 370mm arms I think the 795mm number must not be the number I was thinking it was. They say "diagonal" and I'm trying to figure out the distance between the motors. Oh well, my opportunity cost for my goofing around with arm size is now higher than the cost of 6 400mm arms
Motopreserve
Drone Enthusiast
Have you built the frame yet???
crayfellow
Member
obviously not or I'd have a better idea of its dimensions :-D
Motopreserve
Drone Enthusiast
I couldn't really understand the wording of that last post, so I figured I'd check
crayfellow
Member
hahaha! goofing around meaning studying whether I can get away with the arms I have or not. I'm certain now that if I need 15" props, I need 400mm arms. I should have just ordered them in the first place.I couldn't really understand the wording of that last post, so I figured I'd check
Motopreserve
Drone Enthusiast
If you got them here in he states - I'm sure P will exchange them.
EDIT: that is, as long as your "goofing around" hasn't mucked them all up!
EDIT: that is, as long as your "goofing around" hasn't mucked them all up!
crayfellow
Member
hahahaha, usually my goofing around involves looking at a computer screen! it hasn't gotten physical.If you got them here in he states - I'm sure P will exchange them.
EDIT: that is, as long as your "goofing around" hasn't mucked them all up!
Motopreserve
Drone Enthusiast
Then you should be all set.
Mactadpole
Member
I was wondering about that 1.2" number with 15's on 375mm arms. I have the 400mm arms and I'd say there is about that or a little more between the 15" props. I know with the 16" props on the 400mm there is only around 15mm gap.
Motopreserve
Drone Enthusiast
I think I opened that can of worms. The Quadframe quad I have definitely can fit more than the stated size prop. But the hex cuts off more space with the angles.
crayfellow
Member
Yes, that makes much more sense. Serves me right for ordering frame parts before I had the rest of the rig sorted.
crayfellow
Member
can I send you an invoice? KIDDING!!
I have 400mm arms on the way, and may make a simple fun/practice quad on the cheap with the 370mm (I'll put that in another thread). I have a feeling an undergrad intern, or myself, or anyone else new to all of this is going to be awfully intimidated by the big rig.