Together we make EasyVFR
Notifications
Clear all

Question Engine-out glide range?

10 Posts
6 Users
1 Likes
876 Views
edea88e0d5a8c51610f60ee8ff41c2e3?s=80&d=retro&r=g
Posts: 88
Beta tester
Topic starter
Estimable Member
Joined: 4 years ago

I heard some competing apps show a glide range "circle" on the map. If the engine out glide ratio would be added in the aircraft profile the glide range could be plotted on the map, based on wind an present altitude, maybe visible after tapping an "emergency button". Would be even more cool if it would take the terrain elevation into consideration as well.

Any plans to implement such a feature?

Best

Albrecht

9 Replies
5c1242ce1c84de60ae1ea618ae44df33?s=80&d=retro&r=g
Posts: 971
Admin
Noble Member
Joined: 4 years ago

This feature is getting requested quite frequently over the last years. To be honest always when I start to think about implementing it I end up with so many different variables and questions that influence the final shape to draw that I always end up throwing it away because I think its useless. For example should we draw it based on "theoretical"  values like engine out glide ratio or should we use the current GPS GS and apply forecasted wind aloft so the user immediately sees the effect when reducing his speed to optimum glide range speed? Personally I think the latter is much more useful

A recent request for the same feature by another user made me ask Rik (our youngest collegue studying aerospace science) to think things over and come with an advise, so I guess there is a real chance this feature will be implemented not too far from now 😉

 

Reply
3 Replies
a82ba4be1a792ce8fff251489ebb3429?s=80&d=retro&r=g
Joined: 4 years ago

Estimable Member
Posts: 123

@rob-weijers

Hi Rob, I totally agree with you, because I believe engine out situations ask for immediate actions and decisions (navigate, evaluate and decide) which furthermore can be influenced by sudden changes ( meteorologically, technically, topographically or even medically) and therefore should not be hampered by an theoretical fixed virtual value, which possibly can restrict proper immediate decision.(i.e. target fixation) Just my personal opinion, must not be the absolute must.

Regards  

Reply
edea88e0d5a8c51610f60ee8ff41c2e3?s=80&d=retro&r=g
Beta tester
Joined: 4 years ago

Estimable Member
Posts: 88

@louis

While I understand you concern, distraction can be a general problem with any FMS gadgets. This is in my view not a concern particular to this feature request.

I do believe, that depiction of an unobtrusive glide range area can actually help my situational awareness enroute. Is this next airfield / golf course / farm within glide range, well, barely...? Maybe I should climb another 1000 ft?

Because I learned flying in gliders, I am eye-hopping from contingency field to field anyway and the glide range feature would certainly help with that habit, especially in rough terrain. So no, I do not see this as an emergency function to be used only after loss of the engine, but as a situational awareness tool. And it does not need to be perfect, a pilot must always account for wind drift and do the final triangulation by eye. We should be used to that.

Cheers

Albrecht

 

Reply
a82ba4be1a792ce8fff251489ebb3429?s=80&d=retro&r=g
Joined: 4 years ago

Estimable Member
Posts: 123

@spornrad

Hi Albrecht, 

I also started my career as glider pilot and flew with sailsplanes quite a long time. That's why I agree with your last statement completly. Being FI also, I just realized in growing cases student pilots and even PIC's within the past heavily only fixed on onboard MFD's or even portable notebooks a.o. gadgets, thus not surveying surrounding situation anymore and thus loosing SA! I just wanted to state the problem of overloading the PC between the ears!

Other than that I agree with you that such feature can assist alot!
with best regards cheers Norbert
Reply
edea88e0d5a8c51610f60ee8ff41c2e3?s=80&d=retro&r=g
Posts: 88
Beta tester
Topic starter
Estimable Member
Joined: 4 years ago

Would be more useful if it uses actual wind aloft estimates. Will be challenging because EV is lacking actual airspeed information, I understand that. However, maybe it could indicate EVs actual airspeed "guess" (maybe from wind forecasts) and thus allow the pilot for a sanity check / correction of glide range when comparing EV airspeed guess and actual airspeed.

What about a "engine out panic button" that activates the following:

The initially theoretical range based on glide ratio is now replaced by actual delta(altitude) and GS math when some time into the glide.

A definitive gain in safety would be in my view a terrain indication, e.g. a "relative terrain engine out" mode that would show what areas are reachable at best glide.

Waiting patiently 🙂

 

Cheers

Albrecht

Reply
cce21ae5caa1930c1668863a93da7c07?s=80&d=retro&r=g
Posts: 1
Beta tester
New Member
Joined: 2 years ago

Hi! Bumping this thread with my 10 cents ? 

I think an engine out glide range should be based on actual winds aloft and L/D at optimum speed.

It might be a bad idea calculating glide range based on any form of dynamic airspeed modelling. Why?

1. A typical SEP, MEP, SET or MET would have such a narrow useful engine out glide speed range that showing glide range at actual speed at typical cruise speed (way faster than optimum glide speed) probably would present a nonsensically short glide range the first 30 seconds after the engine quits. That is just when you need it the most.

2. For a TMG the optimum glide speed range is wide. That means it would most probably be far better, if you wanna go for dynamic glide speeds, to make an McCready calculation based on optimum speed for the actual head- or tailwind penetration that you face. It would also need to take in account the airmass vertical movement. This is a bit on the complex side to code and this solution would also need a reasonably precise pressure altitude input and some sort of speed to fly indication constantly updating and providing information without the pilot having to constantly look at the screen. Not to mention the need for speed polar input for every type you fly.

 

In light of this, keep it simple. Use winds aloft, because they heavily influence glide range, and airspeed for best L removed link Present that airspeed somewhere on the screen at all times. TMG pilots should have the training and experience to be able to adapt their glide speed to a dynamic airmass anyways and SEP, MEP, SET and MET pilots most probably haven´t got the aerodynamics to do anything about it so they should stick to their published speeds...

 

Sorry for the long comment! Fair winds and healthy engines to you all ?

 

/Nick

Reply
5c1242ce1c84de60ae1ea618ae44df33?s=80&d=retro&r=g
Posts: 971
Admin
Noble Member
Joined: 4 years ago

Hi Nick,

 

Thx a lot for your comments! This feature is subject to a lot of discussions here internally over the last months, and we can't seem to come to a good compromise ;-). Its definitely on our short term wishlist, and your input will sure help!

 

 

Reply
1 Reply
Heli.Lamb
Beta tester
Joined: 4 years ago

Estimable Member
Posts: 124

If you decide to implement this, please also give us the option to turn it off.

Reply
b5c830c40d747fdb5ae6278e1fc0a4e0?s=80&d=retro&r=g
Posts: 238
Beta tester
Reputable Member
Joined: 4 years ago

+1 for the optional Turn off button!

Reply
Share:
My cart
Your cart is empty.

Looks like you haven't made a choice yet.