Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Dexacare, Mar 28, 2016.
The nose gear has an Oleo.
Still don't want the gear to come up with the weight off the nose but still firmly planted on the mains. Better than none at all though I suppose.
Probably, but don’t Mooneys have a pitot pressure switch to disable gear retraction below a certain speed?
Beechcraft certainly uses a speed switch on the Duchess, not sure about any of their other types, far from foolproof judging by the number of Duchess aircraft where the gear has retracted on ground!
I think Raptor has a speed switch but something must not have been right there. A squat switch on the nose oleo would at least prevent inadvertent retraction sitting on the ground.
Only way in this configuration LG system, must be installed devise that mast be MOVED before activate LG lever, like on most Russian aircraft.
Maybe go (crazy) high tech and use the tire pressure sendors now fitted to new car valve stems? Tire pressure decreases a little when weight is off a wheel. With some sort of temperature accommodation or comparison between tires (months of "groundbreaking") development, false alarms could be minimized.
Another "first" for the brochure.
.......which will probably turn out to be 'lasts.'
The team made some good progress, Peter actually taxied the airplane (minus wings, canard and doors) under its own power. You can feel the sense of accomplishment after the countless thousands of hours of work in the latest vid.
You can ***** and moan about the details and have an opinion on the worth of it all but whichever way you cut it, it remains a seriously impressive achievement which I really hope they have the resources to complete and test fly at the very least.
In all fairness, the BE-76 is used almost exclusively in the training environment where these type accidents are most prevalent. Add to that most high volume flight schools specialize in low volume maintenance. I flew a Duchess from a pilot mill once and it was in pretty bad shape mechanically.
The amount of work acomplished is certainly admirable, but meeting design goals would have been the "seriously impressive achievement".
Latest video shows some more taxi testing and another major problem with the redrive. One bearing was really torn up. Other people had commented when it was last disassembled that it didn't look good. Peter dismissed those comments as normal wear and put it back together. Now it's really toast so he put the old drive back on but it lacks the oil passages to feed the C/S prop. Peter seems intent to start flight testing soon before properly solving the redrive issue. You should never start test flying until everything is 100% ok. The engine/ drive package lacks sufficient running time at high power to be considered flight ready IMO. He needs the C/S prop working to collect any useful flight data outside of basically proving it flies well (or doesn't).
Intercooler outlet temps, oil temps and EGTs look high with the power settings being run. I predict the oil temps will be extreme in flight given the placement of the cooler and it having no ducting at all.
Peter needs some experienced eyes on the redrive if he wants to continue on this path, ditto an experienced turbo diesel guy.
Probably preaching to the choir here, but EVERY test flight that Scaled did, we went into the pre-flight meeting with the working assumption that we WERE NOT going to fly today, and it was everyone in the room's job to convince everyone else that everything was perfect (including the pilot's previous night's sleep, the weather, the runway condition, as well as every **** thing on the airplane) in order to say "yep - let's fly this thing". If it wasn't - we didn't fly.
I try to impart that philosophy to all EAB pilots in Phase I as well. And for Cthulhu's sake, no audience and no family members, and you don't tell anyone when you're planning on flying. NO expectations.
What wusses we are...
Depends on your perspective:
It just dawned on me that maybe he thinks 'radiators' means something that cools by radiant heat, like a radiant electric heater.
I get the impression Peter is aiming for Oshkosh this year. I hope that is wrong and doesn't enter into any flight test considerations. Given how many setbacks and do-overs during construction there have been, it should be clear there will be many others before this is ready for prime time.
I saw a post asking Peter if he still thought the plane would meet the 3600 mile range projections. No answer of course. Was the poster completely naive or just trying to rub salt into the wounds after the weight and fuel flow revelations?
The latest vid shows Peter running the engine at what is described at TO power for a few minutes however, this is nowhere close to TO power. Max throttle was under 50%, fuel flow was 7.6GPH and rpm 3200. HP was probably around 135 which is about 2.5 times less than what the actual TO power is claimed to be.
Peter has finally added a guide vane array to duct air to the HEs on top of the engine but there is nothing for the oil cooler. In answering one comment about cooling, Peter seems convinced it will cool better on the ground with the cowling installed. That's highly doubtful. He continues wasting time on the complicated articulated intake scoop design and actuation and at one point describes the old redrive now fitted as "bulletproof" even though it's only run a handful of hours and almost none at full rated power.
I still see fluid lines running close to airframe/ engine mount members and the turbo stuff looks way too close to other parts from a thermal point of view. I hope Peter looks at these things before flying.
Kudos to Jeff and Devon on their sanding work. Won't be long before canard and wings are ready to be fitted.
I have designed German diesel engines for 4 years and it is more between 110-115hp if I didn't make a mistake (calculated on the fly on my phone now)
Depending on your assumptions I reckon it's more like 150hp.
7.6GPH × 3.78L/USG × 0.832kg/L ÷ 215g/kW.h ÷ 0.746hp/kW = about 150hp
But Ross's point still stands.
I guess with a fixed pitch prop you don't want to make full power on the brakes because it will overspeed very quickly once you're moving
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