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Bristell Energic (H55) certified electric plane

the relevance to the Bristell Energic is…

There was a lovely looking Bristell that I used to watch doing touch and goes at my local field. It won’t be doing any more, because the pilots are now dead. The electric technology for the power plant is great, well done to those involved. We could make airplanes 70-80 years ago that could recover from spins. In terms of airframe progress, I don’t buy into it. Sorry, just my opinion on them.

Buying, Selling, Flying
EISG, Ireland

And again, because nobody ever looks at the figures and does some basic arithmetic.

From the H55 website:

  • Max power: 90 kW
  • Max continious power: 65 kW
  • Battery capacity: 50 kWh
  • Max endurance: 90 mins
  • Payload: 200 kg
  • MTOW: 850 kg
  • Battery: 8650 and 21700 battery

The most likely airframe for this is the Bristell “Classic” VLA/LSA, powered by a 100HP Rotax engine. Which is not yet certified.

Some data:

  • Empty weight 705lb (320 kg)
  • MTOW 1323lb (600kg)
  • Useful load: 280kg
  • Stall speed: 43kt (clean)
  • 100 HP Rotax

A few simple calculations on power and range:

  • it could sustain 33kW for 90 minutes, so let’s say 30 kW cruise for 1.5 hours (45 kWh) allowing 5 kWh for taxi and climb, and assuming 100% efficiency.
  • That is around 44hp

So that is at least plausible, if a bit slow, I would guess 60-80kt cruise speed.

so around 80-100 NM range if one is happy with only 15 minutes reserve.

A few on weight:

  • Payload of 200kg would indicate that it weighs 80kg more than the Rotax version
  • The Rotax weighs around 60kg, so the battery + electrical motor weigh around 140kg

That is not plausible at all. The cells they use have an energy density of up to 300Wh/kg. This means the battery alone will should weigh 166kg, and that is before you mount it, cool it etc.; for comparison – the Tesla Model 3 battery delivers 75kWh and weighs nearly half a ton, so scaled down to 50 you will look at 300kg. THe truth will be somewhere between these two weights, as the aircraft version may not need some of the cooling required for the automotive version.

Of course they could increase the MTOW of the aircraft by 150kg (600kg was clearly the US LSA limit, the EU VLA is 750kg).

Biggin Hill

TLDR version:

An aircraft that flies 100 miles in 1 hour and 15 minutes which that has been designed for 150kg less weight than required to fly that far. Which has not been certified yet, even at the lower 600kg it has been designed for.

Biggin Hill

Cobalt wrote:

The most likely airframe for this is the Bristell “Classic” VLA/LSA, powered by a 100HP Rotax engine. Which is not yet certified.

The airframe (as can be seen on the H55 homepage) is a Bristell B23, currently being certified.

mh
Aufwind GmbH
EKPB, Germany

WilliamF wrote:

There was a lovely looking Bristell that I used to watch doing touch and goes at my local field. It won’t be doing any more, because the pilots are now dead. The electric technology for the power plant is great, well done to those involved. We could make airplanes 70-80 years ago that could recover from spins. In terms of airframe progress, I don’t buy into it. Sorry, just my opinion on them.

Can you please be explicit? The pilots are dead? Why? And what’s the relevance to the B23?

ESKC (Uppsala/Sundbro), Sweden

Airborne_Again, I think it is relevant. 4x fatal accidents in 6 months on a very small fleet size?

https://aviation-safety.net/wikibase/type/NG5

Anyone know how many NG5’s have been built? They should not be sold without a parachute.

Channel Islands

pistonfever wrote:

Airborne_Again, I think it is relevant. 4x fatal accidents in 6 months on a very small fleet size?

Indeed! But why not say so straight out rather than giving these subtle hints? People are not usually up to speed on the accident statistics of every aircraft type.

ESKC (Uppsala/Sundbro), Sweden

WilliamF is speaking about a recent fatal accident in Ireland on a Bristell NG5.

It’s an accident that comes way too close to home for me. I lost a very good friend in it, which I’m still coming to terms with.

I suspect WF was speaking also from a sense of loss, hence why his post might not have been that clear.

What’s not obvious to me though is how he knows the video is of a Bristell?

EIWT Weston, Ireland

dublinpilot wrote:

What’s not obvious to me though is how he knows the video is of a Bristell?

All I did was type the words Bristell Spin into YouTube. Some folks close to the event you speak of were showing me the same video. The LAA TADS for the Bristell says “Intentional spinning is prohibited”. Plenty of threads on PPrune etc about this topic. Crashes close to home and when there are fatalities coupled with design shortcomings, you tend to pay attention to those events. Certain local Cessna 150, Skybolt and BD5 accidents all jumping to mind where the aircraft design let the pilots down.

Buying, Selling, Flying
EISG, Ireland

WilliamF wrote:

Certain local Cessna 150 … accidents all jumping to mind where the aircraft design let the pilots down.

What happened with the Cessna 150 which was design related? I thought the 150/172 designs were one of the safest around.

ESKC (Uppsala/Sundbro), Sweden
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