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Forum Index : Microcontroller and PC projects : At last - a proper use for a control system.
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PeteCotton Guru  Joined: 13/08/2020 Location: CanadaPosts: 543 |
Cool model harrier doing VTOL. On his other videos he shows that he's using a P&ID to stabilise it. https://www.youtube.com/watch?v=t66QM0X26h8 Edited 2025-01-08 07:11 by PeteCotton |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1360 |
Incredible....  I'll be watching this, over and over  |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1360 |
Can't find it now but there was a video about drone development and I was quite surprised that they did fine with a 250Hz PID loop-rate. Naturally, as processors got faster, they went beyond 1KHz but sometimes, faster is not always better. PID needs error to function at all and if one is not careful, this could lead to instability. I am running 1KHz on the PicoMite, only because it is the most common for CNC control but it's overkill in many cases. |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 5056 |
Hi, They are using a drone flight controller to stabilize the plane. The complexity is that this plane seems to have a single (or dual) ducted fan, and in stead of controlling individual motors, they control servo controlled air flow. The essence for this was already implemented in arduino (read: arduplane). The tuning is the difficult part (as is building the plane light enough for this application, since ducted fans generate high speed air flow, but not a lot of thrust). The real difficult part will be the transition from VTOL to normal flight. The air flow directors rotate, and in the control algorithm Z becomes X direction for thrust, but the sensors do not rotate. So there is a control algorithm needed that can rotate output functions. That is typically not implemented in the flight controller plaforms. Volhout Edited 2025-01-08 18:11 by Volhout PicomiteVGA PETSCII ROBOTS |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7857 |
That's a lovely model! Believe me, you can't beat the racket from a Harrier! Rather noticeable when you are working in buildings at Warton aerodrome. :) While I was there they wouldn't let them use VTOL because it melts the tarmac in that area. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1360 |
Back in the 90's I was at a meeting with McDonnell Douglas and there just happened to be some airshow or something going on and my host took me to watch. The American AV-8B Harrier came hovering over the Mississippi, under the bridge, stopped and turned to left, bowed to the crowd and did the same to the crowd on the right. Then it pointed upwards and shot away. Some random guy shouted "America baby!" I shouted back "British development, actually"  |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7857 |
At Warton and Samlesbury they have English Electric Lightnings (just the shells, I think) on display stands. Apparently they were very popular with the pilots and were, effectively, just a pilot sitting on a pair of turbo-jet engines. Many pilots got told off for just pointing the nose up and letting it rip. The rate of climb was phenomenal. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1360 |
I'd take a slap on the wrist, any day, well, every day just to do that. Always loved the Lightnings  |
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| PeteCotton Guru Joined: 13/08/2020 Location: CanadaPosts: 543 |
I noticed that as well. On the real Harrier they vent air from the engine out to the wing tips and tail so that they can balance/turn the plane without needing airflow over the wings. If you look closely at the model - it looks like he has small propellers/fans in the wingtips to achieve this balance (with the four vector thrusters providing lift). Yes - I haven't seen that happen yet. I suspect it's going to be very tricky. Not least because you're going to need to have sufficient airflow over the wings to create lift before you lose the upwards thrust. Maybe he has to go to a much higher altitude to transition so that he has a few seconds leeway in which the model can drop a bit. |
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| PeteCotton Guru Joined: 13/08/2020 Location: CanadaPosts: 543 |
I probably should mention that one of my brothers collects planes, and he has a lovely lightning and harrier. They look amazing. Edited 2025-01-09 02:14 by PeteCotton |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1360 |
Harm and Pete: What about his F35? It's doing VTOL and full flight(?) |
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| PeteCotton Guru Joined: 13/08/2020 Location: CanadaPosts: 543 |
The F35 has two separate power plants. A lift one (mounted vertically behind the pilot) and a thrust one at the rear of the plane. Both can be running at the same time during the transition (from vertical to horizontal flight). The harrier has four thrust vectors which must turn at the same time from downwards pointing to rear pointing. He could get the same effect (as the F35) by controlling the front pair and rear pair separately - but that would be cheating. I suspect there's a 45 degree angle or something that would give him the required thrust - but that might pitch the nose down (depending on how it's balanced). It's a tricky one for sure. Edited 2025-01-09 04:38 by PeteCotton |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10232 |
For anyone who doesn't know about the English Electric Lightning have a look at this I stopped flying as a hobby a few years ago. Before that I built and flew a Vans RV9A aircraft  Shown here at the LAA rally (like a smaller Oshkosh). The reason to raise this is that In the UK newly built aircraft have to be flight tested by a qualified test pilot. My test pilot for G-OPVM was a retired Lightning pilot |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7857 |
Thanks Peter. There's some interesting stuff about the Lightning in there. I didn't know that they even stored fuel in the flaps! G-OPVM looks really nice. :) Flying has become a very expensive hobby now, I'm told. One of my friends sold his aircraft some time ago, but kept going with a hang glider for a short while after! Now downgraded to a kayak. lol Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| PeteCotton Guru Joined: 13/08/2020 Location: CanadaPosts: 543 |
One of my favourite stories about the Lightning. https://en.wikipedia.org/wiki/Holden%27s_Lightning_flight They are surprisingly large. But one of my absolute favourite aircraft. Up until recently you could book a flight on one in South Africa, but I think they eventually got grounded after a fatal crash. We looked into the legalities of flying one in Canada, but it was an absolute no-go. Apparently there's no redundancies on board for a lot of systems and the hydraulics are famous for double failures (I also suspect the fact that having a civvy plane that can do Mach 2+ makes them a bit uncomfortable) - so, sadly, I don't think any country will ever authorise them to fly ever again. If you're wondering how you get flights in a single seater fighter, the South Africans were using the T5 which was the two seater trainer version. https://www.youtube.com/watch?v=5hLvufAknW8 Edited 2025-01-13 06:48 by PeteCotton |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 7857 |
Thanks Pete :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 5056 |
Hah, I once built and flew an RV9 model airplane. But the real thing is quite a different story. Envy you Peter... Volhout PicomiteVGA PETSCII ROBOTS |
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| PeteCotton Guru Joined: 13/08/2020 Location: CanadaPosts: 543 |
Well, if you ever find yourself in Western Canada, drop me a line and we'll go pay a visit to the Harrier. I'll even buy the drinks  He has it parked on the patio of his pub. We have some cool ideas as to what we can do with some simple PLCs and noise/smoke/lights for the summer time.  |
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| PhenixRising Guru Joined: 07/11/2023 Location: United KingdomPosts: 1360 |
PLCs ??? Heck no. Mites are FAR superior  |
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| PeteCotton Guru Joined: 13/08/2020 Location: CanadaPosts: 543 |
 While I do agree, ... we have a surplus of out of date PLCs lying around that we will never use on a "real" project. Mites would be wasted on this - going to keep them for fun projects! |
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