WWI Replica Safety

[Joe Perkel]

Sid,

I need to be careful here, and try not to interject my own bias relative to choices made regarding my own project. Instead, I will make a conscious effort to simply say what has been, and continues to be on my mind as I prepare for this build.

There can be no denying the fact that a wood and wire aircraft is not as crashworthy as more modern designs. This is a tough call to make, one that requires a tug of war between conscience and desire.

The one thing going for most of these replicas in this weight class is reduced inertia,... only that should come into play more so with some degree of continued airframe control until impact. This wing failure accident brought Gontermann down at some unknown but, obviously unacceptable rate of descent.

Clearly, most G.A. accidents are survivable, the data is undeniable in that regard. So for the purposes of this thread, we are in fact then, preparing for this survivable accident where crashworthiness is concerned.

What to do about this???......Possible remedies?

1) Modify structure to reflect more modern advances,...examples of which would be, airfoil shape, airframe material selection (4130 tubing),..etc.

You have several gains here that I can see,... a more simple cost effective method to build, better crashworthiness, better lift with new airfoil. Authenticity of course, is lost. The problem that I have found with this, is the simple fact that it would be an entirely new design. Then the next problem becomes, is that I am not a qualified aeronautical engineer.

This is not to say that one needs to be an aeronautical engineer. The home-built industry has generations of examples flying around out there designed by average Joe's (pun intended). No,... this is more of a personal comfort decision. Steve Culp told me that he had learned from Curtis Pitts to take any existing design and shape it into what you want. Perhaps so,...but not for my first time out.

2) Install as you mentioned, a BRS system.

Here, the main advantage is giving the pilot an actionable option in the event of complete loss of airframe control, (from whatever cause), at an altitude that negates the egress option, (if so equipped anyway). Clearly, Gontermann would have benefited from a successfully deployed system.

I am continuing to study this issue with regards to my own project. Cost for my gross weight is approximately 8K (US), and about 38 lbs. Of keen interest is the installation in Ted Calahan's spectacular aluminum tube Graham Lee Nieuport 11. Nieuport 11 N124TD BRS-750 Softpack Installation This location on my own chosen design, housed a secondary fuel tank.

Regarding a BRS installation, there are several questions to be answered with regard to a wood and wire craft in the weight class of a Sopwith Baby, but of primary interest is.........

1) What local loads on the structure would be imparted by the opening shock of deployment, and would any modifications be necessary? This is an open question I have shelved for the moment to be answered at some future date.

2) May very well have to scrap side by side seating, in favor of single as original.

3) How to mitigate the hazards of the deployment system itself.


The Case for Authenticity in WWI Replicas

This discussion is about crashworthiness of an authentic design, which in my opinion, is clearly shown to be not up to modern standards. Jumpinjan once said to me on this very forum,..."Joe, haven't you ever heard that with authentic aircraft, come authentic risks"? A damn profound statement, that I have not forgotten.

So why do it then?

1) I suspect this has less to do with flying, and more to do with the machines themselves and the era in which they flew. After all, everyone who has ever built one of these was faced with a myriad of other choices. I hope to mitigate these risks as much as practical without robbing the machine too much of what truly makes it unique.

2) Because there may not be a second project due to logistical, financial, personal,...etc...reasons.

3) Clearly, authenticity has historical, emotional and, monetary value.


Conclusion

Here's the thing......

If 70 % of accidents are preventable by the pilot, then that's where I want to really, really focus,...me! I have to continuously remind myself that yes,..It can in fact "happen to me!" That other 30 %, Well now,...that's why we're here, to tweak that in our favor as much as possible!


Spectacular stuff Sid, very thought provoking,...thank you!

[Joe Perkel]

Sid,

...I forgot to mention, the primary reason for choice of a float plane design.

Most would assume because I live in Florida. Considering only 3 public use seaplane bases and, significant waterway restrictions logistically it is not a good choice.

I chose it for the simple reason of mitigating an extremely common replica accident,.... runway excursion, with subsequent nose-over.

Clearly you swap risk of drowning for,... say impalement with a broken structure, in similar conditions but,.... the runway excursion issue was too common to ignore.

[Butch]

Build it authentically as possible. You can always fly a Cessna.
Pete

[j ferguson]

Guys, Forgive me for having a strong negative opinion about something here, but I hate the idea of installing a parachute to lower you and the airplane to the ground, in the event that you have a serious problem that compromises it’s controllability.

In addition to the likely embarrassment of showing up at Aunt Minnie’s lawn party dressed to kill, so to speak, in a DVII, there are several other problems. What if the problem is a fire? How are you going to modify the airframe design not only to take the load on the airframe imposed by the parachute, but the loads of ground impact? For example think about what happens if you come down with the fuselage spanning two park benches such that a significant buckling load tends to fold the fuselage at the cockpit? Remember, you are going to be along for the ride and you are going to have little, if any, control of where you go or how you land once you’ve deployed this thing. Also, if your cockpit is at all original, it looks as though it would be a terrible place to be in this sort of landing, sort of the “Spanish Maiden” of aviation.

The WW1 planes I’ve looked at closely seem to have very cramped cockpits, which do not look likely to have room for both you and a parachute should you choose to wear one, rather than build it in. Also, it appears that these planes will be flown mostly around airports and at altitudes too low for parachuting.

Maybe the best idea is to fly from a big field where you can land straight ahead no matter what happens, until you do get to altitude, such as a lake in Joe’s case.

Sid, I know you think the built-in parachute is really a good idea. Help me with this. Maybe I’m missing something.

[Joe Perkel]

The question of viability of a BRS system with a full scale authentic WWI replica, is worthy of closer examination. For the purposes of this thread, and for planning my own project, I just composed an inquiry to BRS Systems Inc. to determine compatibility and, or possible modifications necessary. I will inform the members what I find out.

The idea behind this being it's a final actionable option in an otherwise hopeless scenario, from modestly low altitudes,..ie 300' up to pattern altitude.

The scenario being that a particular event was survived, ie... midair collision, catastrophic structural failure, loss of control...whereby the impending surface impact would most certainly not be survived. The alternative being having to sit there with nothing to do but ride it down.

I believe that Cirrus was the first production aircraft to introduce the system, the ultralight industry had been using this for years. Systems can now be retrofitted into most light G.A. aircraft and, utilize a solid rocket deployment of the main chute, with the apparent wind (not altitude), being the critical canopy filling element. A successful outcome requiring a successful deployment, which comes with it's own set of problems. Structural attachments as noted and, unimpeded deployment of the system. There have been documented cases of the rocket and or chute being impeded by deformed structures, rapid rotation, and poor installations.

BRS claims a descent rate of 15 - 28 fps under canopy with a properly matched system. Here is an interesting calculator to plug-in some numbers, (scroll down to the velocity calculator).......Unit Conversion Calculators :: Weight, Volume, Length, Pressure, Energy, Calorie, Velocity, Temperature

What if the problem is a fire?

Fire,....bad news for any aircraft,...particulary catastrophic for a WWI replica. This one simply has to be prevented before takeoff. If not, you can consider yourself to be especially unlucky. The hazards of the BRS rocket deployment, also need to be dealt with and, to my knowledge can be successfully employed in fabric covered aircraft.

Deploying a BRS in this scenario, would likely only serve to increase the altitude from which you would end up leaping from.

Conclusion?

If compatible with authentic replica construction, then it seems to me that the questions of increased costs in weight, complexity, and dollars,... needs to be weighed against the probabilities of the types of accidents it is designed to mitigate. I have not looked at this close enough to come to any conclusions yet.

[Machinbird]

Originally Posted by Butch

Build it authentically as possible. You can always fly a Cessna.
Pete

Hi Pete. I can't fly Cessna's too well, the gyro's keep breaking

I picked out the Fokker D.VII as a candidate build a number of years ago because the steel tube frame had the potential for providing a good load path for a BRS chute. The wing center section appears to have enough room for the BRS chute pack and deployment rocket without disrupting the aircraft external lines. The most pertinent question is where to stow the deployment handle without making it attractive to the curious. So why the emphasis on the BRS type chute?
When I first started flying military jets, it was explained to me that I would be sitting on a cannon that would throw me out of the airplane if I simply pulled a handle, and if you pulled the handle at the wrong time while on the ground, well too bad. I was a little chary about sitting on this potentially dangerous device but I did want to fly the jets, so, knowing what a klutz I could be, I resolved to be extra careful and respectful of the seat.

After a while in aviation, I began to see some saves first hand: My wingman escaping an unrecovered inverted spin, an inadvertent throttle retard during a cat shot, a catapult tow hook failure on launch, an ejection from a burning plane as a result of anti-aircraft fire. Not all these situations were 100% saves. Some were injured, some were lost, but in general one's odds of surviving severe aviation adversity were significantly improved by ejection seats.
I am not advocating ejection seats for replica aircraft. The systems are too large, too expensive and too demanding to maintain effectively in most private aircraft situations. I do advocate the BRS chute because it has many of the same advantages as an ejection seat, can be inobtrusively installed, and is maintainable, and while not inexpensive, it is not prohibitively expensive. Is it a perfect solution? NO. As Joe pointed out, it won't help you much in a fire. I'm not quite so concerned as John about arriving "dressed to kill" at Aunt Minnie's party. The odds are fairly long on that scenario, or on the park bench scenario. Besides, with a plane under a chute, people have time to get out of the way. Go to the BRS website and look at some of the saves. Those could be you!
Sid

[j ferguson]

brs sounds better than i'd imagined. wing installation on a DVII would get it near the "pre" and likely "post" catastrophe CG. I suppose that if you had a circumstance in which you could use it, the issue of the direction of sudden deceleration while sitting in a "prickly" cockpit is moot.

What is the minimum altitude from which these can be effective? Is it higher than the altitude from which you'll be doing all those fly-bys?

I keep forgetting the formation flying which seems another likely hazard to which less interesting planes are not exposed. I suppose that the issue of getting down in one piece from an "event" has as much to do with the operating environment as it does to the potential twitchiness of these planes.

I continue to vote for flying out of a really big field where you can land straight ahead from any altitude that won't allow a turn. maybe there aren't very many up your way, but there are a few in Florida, mostly old training fields.

[Brad]

Hank, check your PM. I sent you a couple safety/engineering questions regarding what I'm planning to do with the SS DI that's been collecting dust in my garage. lol

[baldeagle]

Don't forget, the most dangerous part of flying is driving to the airport. While my local TV news will report the crash of a Cessna 150 in East Nowhere, Montana, they conveniently ignore that on average over 100 people die each day in car accidents in the US.

It may be apples to oranges, but still, in 40 years of being around WW1 aircraft and replicas, and almost 30 years of flying them, I can only think of one instance of structural failure (one fatality) and one story of a mid-air (no fatalities). Perhaps others know of more.

I personally wouldn't consider putting a ballistic chute in a WW1 replica because I consider the chance of needing it to be so small as to not be a consideration, not to mention weight, cost and etc.

I would say worry about what might happen-- 1: Pilot error and 2: Engine failure. How to avoid these is a long discussion, but those as I see it are the two main issues.

And I'm all for steel tube fuselages as more crashworthy, and one thing I'm sure of when I build stuff is to make sure I have good seat belt attach points, at a good point in the main aircraft structure, not attached to a seat or seat frame. And shoulder harness if possible. Your most likely accident scenario that isn't under your control is an engine out glide into trees or rough terrain.

I always tell my girlfriend that the day I die in an airplane, the next day I would've been hit by a bus. Keep it in perspective.

My 2 cents.




-

[Joe Perkel]

Originally Posted by baldeagle

I can only think of one instance of structural failure -

Baldeagle,

Anything to be learned from this one?,..could you elaborate please?