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pictsidhe

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Joined
Jul 15, 2014
Messages
8,064
Location
North Carolina
The landing gear emergency drop didn't work properly either. Peter thought that was ok as he couldn't think of a scenario where there could be 0V on the battery.
So, gear misbehaves. Belly flop if it has stayed up, or pull the chute if it partially dropped?
 

Marc Zeitlin

Exalted Grand Poobah
Joined
Dec 11, 2015
Messages
695
Location
Tehachapi, CA
If there is a delimination at this place, there is a 90% probability that there will be delamintions elsewhere...
Where'd that 90% estimate come from? Is there some study showing that if one finds a disbond in a layup (and this is a disbond, not a delamination - let's be clear on terminology) that there's a 90% chance that you'll find another one?

and that the glue fillets are insufficient. Did he do bag load testing?
So in this case, the disbond is probably caused by an extremely poor choice of location for aileron hard stops (at the aileron, rather than in the control circuit upstream of the aileron). Pull hard on the stick, put stress on the wing skin bond joint at the hard stop. So a disbond here is only an indication of a lack of understanding of aircraft control system design, not an indication that the fabricators did a poor job of bonding the plane together.

My $0.02.
 

berridos

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Joined
Oct 10, 2009
Messages
961
Location
madrid
Thanks for the delamination/disbond clarification.
Instinctively I was worrying about wrong surface treatment or contamination pre bonding or insufficient fillets. An issue frequently neglected. A wrong peel ply or some other factor and you have the structure significantly weakened.
 

swoodman

New Member
Joined
Dec 28, 2016
Messages
4
Location
Bellevue WA
To be quite fair to Peter while he is showing the positive outlook on all this from his side, I think he's earnestly showing his side of the story. He's unaware of the best or "proper" way to solve a lot of these issues, he's learning as he goes, and while sometimes he acts incredulous at the need for certain tasks he does eventually seem to do them and it seems he tends to come away from those experiences satisfied in the outcome having been worthwhile.

His positive outlook lately has been strained by all the reality catching up, the things he's learning, and I think bit by bit he's starting to get some of it just by being faced with the bill of it all. The lack of experience and knowledge really clearly comes through when seen from the Wasabi video, but it makes plain that he's not so much intentionally hiding the bad stuff, because he simply doesn't know what's bad and should be hidden.

When he has all these deep complicated explanations for how certain things that should just work all have their certain way of making it work, it's clear he's worked it out in his head that it all makes sense and that specific thing might be slightly odd but it works fine; but I don't think he has taken the moment to step back and reflect on all of those quirks in aggregate and whether they add up to the type of machine someone wants to jump into. He's gotta explain every little thing and justify it. He doesn't see that as an issue cuz he has lived with all this knowledge for years. And one or two quirks is probably fine. But everything here has things that just don't quite work right, and so while it works-ish. it's all clearly half-finished prototype stage solutions. And in retrospect when there's a better design worked out (hopefully) he'll clearly see how far he had to go.

But that's the future.

But somewhere I think he knows there are big gaps in his personal experience, which is why despite all of his hubris at times, he still knows enough (I want to hope) to continue to defer to people with experience and real critical eyes when it comes to flying the thing, and has to have inside his mind at least a bit of the real concern that the creature may bite.
I read every post; have done for four years or however long it has been now, and I was (until 2 weeks ago) one of the people with a deposit in escrow (I cancelled without any argument from Peter BTW). I think these comments are spot on. My opinion, is that the truth is in the middle between some of the more extreme viewpoints. On this forum they tend to be very negative at times but the balanced engineering and technical expertise is what I come back for almost every day. I respect Peter for not doing the stupid thing and trying to fly the plane. I also admire that even though he absolutely knew that he wasn't going to like stuff, he was good for Wasabi to post anyway. I hold out hope that those molds will perhaps at some point lead to a lighter and better version of the Velocity - I think we all want that.
 

pictsidhe

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Jul 15, 2014
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North Carolina
What exactly is wrong with Jet A?
It's for jet engines! Diesel engines evolved with a fuel that is a fair lubricant. Jet A has poor lubricity, so diesel pumps that need a certain level of Iubrication are prone to siezing up. Jet A also does not have a controlled cetane number, another important specification for diesel useage.

It would be very useful if someone could research an additive package to 'dieselise' Jet A. May take some dollars, though.
 

Rik-

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Joined
Sep 13, 2019
Messages
400
Location
San Rafael, California
It's for jet engines! Diesel engines evolved with a fuel that is a fair lubricant. Jet A has poor lubricity, so diesel pumps that need a certain level of Iubrication are prone to siezing up. Jet A also does not have a controlled cetane number, another important specification for diesel useage.

It would be very useful if someone could research an additive package to 'dieselise' Jet A. May take some dollars, though.
Jet A, House Heating Oil, Kerosene and Diesel #1 are all the same exact fluid.

In the winter months in NY and NJ, the fuel stations sell Diesel #1 as it does not have the tendency to gel in the extreme winter temperatures.

I've purchased over 500,000 gallons of Jet A and used it in my VW Diesel Rabbit as well as my CAT diesel engines (as well as my Turbines) and never had a problem.

I've heard the rumors of the fuel pumps would not like it but he engine doesn't seem to care.
 

rbarnes

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Joined
Aug 28, 2015
Messages
193
Location
Texas
Thanks for the delamination/disbond clarification.
Instinctively I was worrying about wrong surface treatment or contamination pre bonding or insufficient fillets. An issue frequently neglected. A wrong peel ply or some other factor and you have the structure significantly weakened.
Actual lay up of the carbon fiber is the one place in the project where Peter had someone doing the work that actually knew what they were doing.

and no nothing was sand bag tested, drop tested, or any other kind of tested beyond running up and down the runway at 80+kts
 

pictsidhe

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North Carolina
They are most certainly not the same. Do you really think that oil refiners would use a specific cetane cut and add lubricant additives to kerosene or heating oil? I haven't played with Jet-A, buy I believe that it is pretty close to kerosene. Kerosene is noticeably thinner and less lubricious than diesel. It also smells different, especially when burned. People can spot kero burning diesel cars by the smell. I would mix it with 10% biodiesel, which is very slippy stuff.
I've seen several people kill their pumps with pure kero.
 

Rik-

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Joined
Sep 13, 2019
Messages
400
Location
San Rafael, California
Actual lay up of the carbon fiber is the one place in the project where Peter had someone doing the work that actually knew what they were doing.

and no nothing was sand bag tested, drop tested, or any other kind of tested beyond running up and down the runway at 80+kts
He bounced it pretty good when he slammed it back onto the runway! That's gotta be worth something. After all the wings didn't fall off.
 

Rik-

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Joined
Sep 13, 2019
Messages
400
Location
San Rafael, California
They are most certainly not the same. Do you really think that oil refiners would use a specific cetane cut and add lubricant additives to kerosene or heating oil? I haven't played with Jet-A, buy I believe that it is pretty close to kerosene. Kerosene is noticeably thinner and less lubricious than diesel. It also smells different, especially when burned. People can spot kero burning diesel cars by the smell. I would mix it with 10% biodiesel, which is very slippy stuff.
I've seen several people kill their pumps with pure kero.
Here is what and why I know this to be true.

Every week I was get 1,000 gallons of Fuel delivered to my work for 20+ years. My fuel supplier and my driver were both saying the exact same thing. You ask for Jet A we charge you X, you ask for Diesel #1, we charge you X, you as for house heating oil we charge you X.

What's the difference (Mr. Chevron Refinery in Richmond CA) Price.. other than that not a **** thing so if you want to pay $3/gallon order Jet A. Want to pay more Order Diesel #1, want to pay less order House Heating Oil/ aka Kersosene.

So having done this game for 30+ years I can tell you with a straight face, it's exactly the same stuff.
 

TFF

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Joined
Apr 28, 2010
Messages
13,454
Location
Memphis, TN
When I worked for a regional airline, the only car/ truck to survive the Jet A was VW Rabbits and old style Mercedes. The Ford and Chevy trucks died expensive deaths. I think unless he has said anything different, we are talking #2 diesel out of the pump. That’s what is around here. If your stuff survived , great, but I bet you would be surprise how different jet A and house kerosene is. Both kerosene but A is way dryer. The beauty of a diesel is just about anything combusts. The fuel delivery is what takes the beating. Anyway $3 a gal is retail for Jet A here, bulk it’s about $1.20g.
 

narfi

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Log Member
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Feb 23, 2016
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890
Location
Alaska
different additives will destroy different seals.
Science and politics promote the use of different additives in the different named fuels.

It is my experience that at times all three fuels delivered to my village originate from the same pump, however if they have a customer requiring the newer diesel (with additives for newer diesel engines) that they have to rinse their tanks before delivering jet fuel as it will destroy the seals in our turbine engines.

For the most part I understand the underlying fuel will burn for most of the 3 main purposes (jet/turbine, diesel engine and heaters) but the wrong one in any given system could destroy the seals and or pumps. Those delivering the fuel know what is on the work order as well as the real life end use for the fuel and should ensure that the fuel they deliver is compatible with its end use as well as communicating the reality of the standards of the actual fuel being delivered.

(I am not directly involved in any of this except to receive the fuel for our village generators, so accept my experience with a grain of salt)
 

BJC

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Oct 7, 2013
Messages
11,554
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97FL, Florida, USA
I've purchased over 500,000 gallons of Jet A and used it in my VW Diesel Rabbit
Wow! I drove a Diesel Rabbit about 225,000 miles, but it didn’t take close to 500,000 gallons.

I burned lots of Jet A in industrial boilers back in the early 1980’s at dirt cheap prices. The fuel terminal had take-or-pay contracts for Jet A, the airlines weren’t burning much, more fuel was in transit, so it was cheaper that either natural gas of Number 2 fuel oil. No problems.


BJC
 

Rik-

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Joined
Sep 13, 2019
Messages
400
Location
San Rafael, California
Wow! I drove a Diesel Rabbit about 225,000 miles, but it didn’t take close to 500,000 gallons.

I burned lots of Jet A in industrial boilers back in the early 1980’s at dirt cheap prices. The fuel terminal had take-or-pay contracts for Jet A, the airlines weren’t burning much, more fuel was in transit, so it was cheaper that either natural gas of Number 2 fuel oil. No problems.


BJC
The fuel was for the boat, but if I'm low, the pump flows what the pump flows
 
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Rik-

Well-Known Member
Joined
Sep 13, 2019
Messages
400
Location
San Rafael, California
different additives will destroy different seals.
Science and politics promote the use of different additives in the different named fuels.

It is my experience that at times all three fuels delivered to my village originate from the same pump, however if they have a customer requiring the newer diesel (with additives for newer diesel engines) that they have to rinse their tanks before delivering jet fuel as it will destroy the seals in our turbine engines.

For the most part I understand the underlying fuel will burn for most of the 3 main purposes (jet/turbine, diesel engine and heaters) but the wrong one in any given system could destroy the seals and or pumps. Those delivering the fuel know what is on the work order as well as the real life end use for the fuel and should ensure that the fuel they deliver is compatible with its end use as well as communicating the reality of the standards of the actual fuel being delivered.

(I am not directly involved in any of this except to receive the fuel for our village generators, so accept my experience with a grain of salt)
If you want an "insured fuel" Jet A is going to be the route if you are flying. If you are land based application then it doesn't matter as it's just a price issue not a product difference.

There are a LOT of industrial back up generators that use a Turbine instead of a C18 Cat Diesel Gen Pack. The turbines are cheaper and require less maintenance and the burn the exact same fuel or any fuel you care to put into them. As long as the Specific Gravity is not to far off.

I've heard that for road trucks/cars that you can use the Kerosene if you add some marvels mystery oil but I simply didn't care. Lasted for years and that's saying a lot if you understood how I drive.
 
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