# Tech specs of hybrid powercraft for 115kg airplanes ar motogliders

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#### jbiplane

##### Well-Known Member
I can produce a hybrid power plant of components I produce in my company www.flame-power.com
- 2-stroke engine weighing 4.5 kg
- generator electric starter weighing 2.5kg
- 1.5kg weight control unit
- reduction gear, etc.

So far, this is a rough guess, requiring clarification:
- power of the gas motor 15 hp at 7200 rpm,
- max power of the electric motor during take-off 34 hp
- continuous power of starter-generator in electric motor mode 12 h.p.
- continuous power of starter-generator in generator mode for battery recharging up to 10 h.p.
Capacity of electric buffer electric battery 40ah, weight 8kg to ensure approximately 8 minutes of pure electrical flight.
It seems enough for safe landing if required.

Consumption of a gas engine shuld be less than 4 kg per hour. Says 2 hour motored flight are enough.
Is such parameters optimal and sufficient? You can change everything proportionally. Do I need use gearbox?
If so, the optimum revolution diameter?

#### henryk

##### Well-Known Member
- power of the gas motor 15 hp at 7200 rpm,

- max power of the electric motor during take-off 34 hp
-iff involve CR( 1.3 m diameter) Differential gear (<2 kg) we can get 70 kG thrust force ...

=summary 10 kg/ 15 HP ? =REVELATION !!!

f.e. RAKET 120 (15 HP=70 kG)=

PS= "Capacity of electric buffer electric battery 40ah, weight 8kg to ensure approximately 8 minutes of pure electrical flight. "

=40 Ah , ? V = ? Wh

today LiPo circa 5 kg/ kWh ... 40 Ah * 12 V =480 Wh

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#### Hot Wings

##### Grumpy Cynic
HBA Supporter
Log Member
Do I need use gearbox?
<< >>
If so, the optimum revolution diameter?
This kind of depends on if you are building a series or parallel hybrid.
<< >>
Prop diameter and revolution are going to be constrained by the planes speed range. Slow ultralight type will benefit from slow turning large diameter props. Faster planes tend to perform better with smaller diameter and higher RPM. If the internal combustion engine mentioned is directly attached to the prop (parallel system) you will need a reduction drive, probably somewhere between 2 and 3 to one.

If you can develop a proven series hybrid system, with the specifications mentioned, as a package deal I can think of several small aircraft that could be converted to increase efficiency and/or range. Overall weight and cost will determine if the project is practical.

#### proppastie

##### Well-Known Member
Log Member
Very interesting but. ....price and demand could be limiting. Ask for deposit before you get too far
Possible military drones are a possible market in which case it becomes more feasible economic wise

#### berridos

##### Well-Known Member
Trippling the kw capacity of the system and using a watercooled engine would make the pack highly interesting. 8 minutes is fine as an emergency feature.

#### proppastie

##### Well-Known Member
Log Member
My design is pusher....with 32" model prop turning 5-7k rpm. direct drive.....so right away you see two different requirements......I am looking for off the shelf systems if my current model engine does not work out......I certainly would not want to pay for a development project.....I would rather do that myself. For the cost of some of the E-systems I can buy a flying aircraft here in USA.

#### jbiplane

##### Well-Known Member
I am looking for off the shelf systems if my current model engine does not work out
The project on this screenshot with tech specs I provide already started. Using as donors
- 1500 USD DLE engine
- 300 USD chinese BLDC in starter
+ electronics, we already design in house.

I should deliver working system to customer before April 2021.

Next system I negotiate with canadian investor use BLDC as belt reducer pulley.
Probably I should do myself without investments.

#### proppastie

##### Well-Known Member
Log Member
use BLDC as belt reducer pulley
Might want to add tapped holes to allow for direct drive for off the shelf model propellers ......if the bearings on the DLE are strong enough. but maybe that BLDC is too big as regards blocking the prop blade? Special propellers can get expensive, and most likely a design could try many to get the best prop.

When you examine the 10 or 12mm crank on the DLE you might decide your engines are better.

#### henryk

##### Well-Known Member
Special propellers can get expensive, and most likely a design could try many to get the best prop.
=typicar PPG propellers (1.3 m, 80 kG thrust with CRDiff. gear )

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#### jbiplane

##### Well-Known Member
bearings on the DLE are strong enough
I have collection of DLE gifted by customer who bought my 236cc. I will use DLE on experiments with BLDC on shaft. Yes DLE have TBO ~70hours, my engines ~300 hours. But I an greedy spend few my engines on experiments. Next step will be to use BLDC as a big pulley of belt reducer.

CRDiff. gear
Electrical motors fery flexible due electronic contol. No need to make stuff even more complicate than discussed

#### proppastie

##### Well-Known Member
Log Member
how do you time/match the engine + electric when both are adding power to the whole. will you have a sprag over-running clutch.....seems like an interesting software problem

#### jbiplane

##### Well-Known Member
you time/match the engine + electric
Use simplest approach. Till 60% (software regulated) of the trottle works only gas engine charging battery by says 3A currency (software regulated).
If add more added electrical torque proportionally to x(100-60)

Log Member
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#### henryk

##### Well-Known Member
Electrical motors fery flexible due electronic contol.
=yes, but ICE not=big drag momentum iff not active !
(multiplyed by reduction number =circa 3...)

#### proppastie

##### Well-Known Member
Log Member
does it take a lot of energy/battery power to lockup/partially lock up the electrical portion of the system in order to transfer energy from the ICE?

#### jbiplane

##### Well-Known Member
does it take a lot of energy/battery power
Not at all. At least for 4000w unit we tested.

Parts of 45hp gas motor + 45hp electric motor for EU customer WIP

#### Martin R.

##### Active Member
This kind of depends on if you are building a series or parallel hybrid.
A series hybrid would be ideal for ultralight aircrafts.

Advantages:

- more possibilities to define the center of gravity: the ICE (internal combustion engine) with his alternator, the batterie and the electric motor with the propeller can be installed at different places.

- more possibilities to place the electric motor with the propeller: electric motors are light and - especially in ultralights very important! - are running smoothly.

- the ICE can be operated at constant (his and the alternators best) RPM.

Disadvantage: more weight; alternator and electric motor are separate elements :-(

#### Hot Wings

##### Grumpy Cynic
HBA Supporter
Log Member
Advantages:
You forgot the most important (IMHO) advantage for a US style part 103 ultralight:

High power for good climb in a streamline vehicle and yet not break the speed limit.
There are others.

#### Martin R.

##### Active Member
You forgot the most important (IMHO) advantage for a US style part 103 ultralight:

High power for good climb in a streamline vehicle and yet not break the speed limit.
There are others.
totally agreeable

#### Urquiola

##### Well-Known Member
Global Sources, a Chinese sales site, offers range extenders, combination of Internal Combustion Engine and generator from \$248 or so. NATO sold not long ago a NOS surplus of Sachs Wankel KM-48 engine cores, installed in 'Silent' generators, www.ptsnorfolk.co.uk had some of it. Side seals of all Sachs Wankel engines, from KM-27, KM-48, KM-914, KM-24, KC-27, are same, and same as Aixro engines of today, apex seals differ just in lenght. Blessings +