Jodel D120A performance figures

[betterfromabove]

Hi,

Does anyone know where I might be able to get hold of official performance data online for the Jodel D120A?

Thanks
BFA

[Mark 1]

Official figures are rather scant.

If there is an official flight manual (probably in French), then the CAA should have a copy filed when it was first issued a CofA.

If it was imported directly onto permit, then that route won't be available.

It's probably more practical to brew your own. Treat it as a homebuilt and do a few tests to get enough data for planning purposes.

There is a Jodel UK Yahoo group I believe. That may be a good way of contacting other owners to get started.

[POBJOY]

The LAA office may be able to help,although
there are probably several 'performances' as there will be several prop builders.
Another option is to contact a couple of 120A owners to check their engine/prop/weight config.
There are as many 'homebuilts' out there plus the Wassmer built ones.
The 120A can have a ventral airbrake, and the fuel tank situation can vary.

[betterfromabove]

Thanks guys. Have a French flight manual, W&B schedule and some other information, but runway performance is only experience-based so far.

Will try the Yahoo group again, as well as LAA.

Realise any published data will need to be taken with caution.

Maybe will carry out some tests with an LAA Coach to get some idea of guideline figures.

[Croqueteer]

:)I cruise at 2400rpm leaned. This gives me 100kts and 19/20 ltrs/hr. This is a Wassamer built 120A with a C90. Load 595lbs. and 25ig tank. Not tooo shabby.

[Dan the weegie]

Those are excellent figures. What's the take off roll on grass in nil wind?

[Croqueteer]

About 200mtrs. I think my prop (Evra) is more of a cruise prop. ROC at max is about 500/550 ft/sec.

[Marchettiman]

Wow, must be one hell of a D120....almost as good a roc as a Typhoon!

[Croqueteer]

:O Sorry, senior moment!

[betterfromabove]

Croqueteer - I've been cruising at 2250-2300rpm for 80-85 kts, although have pushed the nose down with near full power (2350 rpm) to get nearer 100kt. So, is 2400rpm sustainable as a regular setting?

[betterfromabove]

I still only have around 25 hours on the D120A, but my experiments at Southern English airfield elevations (a few hundred feet AMSL), middling temps (5-20C) and windspeeds (5-15kt) suggest around 200m for T/O and 300m for landing (with no wheel-braking, but airbrakes deployed). Does this sound reasonable to everyone?

What is noticeable is whether the airbrakes are deployed or not. With airspeed not nailed to 45kt over the hedge and her attitude not spot-on in the flare, it seems you can easily add another 100m to the landing roll if you're not careful.

[ak7274]

With a maximum continuous RPM of 2475 I cruise my C90 at 2300-2350 which leaned out at around 3000ft gives me about 100kts and 17-18 litres per hour in my D117. It has the standard C90 Jodel Evra prop and although I have never measured T/O distance, I have comfortably flown into and out of 300m in nil wind. I don't think I would be happy in anything less.

[betterfromabove]

According to LAA inspector, we're getting around 500ft/min in the climb, (although it likely had 700ft/min when new in the 50's!).

Will try a slightly higher cruise rpm (2350rpm, say) to see what it's like. Does feel like a very nose-down attitude though at that power setting. Is there any noticeable effect on stability in the cruise in this performance setting?

Also, any tips for how to handle on tarmac? That dinky rudder does seem to suggest a certain fidgetiness being possible.....:cool:

[Croqueteer]

:ok:I've seen quite a few C90s and 0-200s stripped and engines that have been run leaned at higher RPM are much cleaner inside, ie piston rings free in their grooves, less soft carbon and cleaner valves. Also the C90 doesn't seem to like 2300rpm, seems to be slightly rough in that rev band. The fact that the Jodel is cruising nose low at that speed means a more efficient regime, with the cranked section acting to reduce drag and providing not much lift.

[betterfromabove]

Croqueteer - fascinating, thanks for the information.

[ak7274]

Not wanting to get into any arguments, but my C90 runs smoothly through it's entire rev range. I find that using 2400rpm is a bit too close to max continuous. The law of diminshing returns also applies to my C90 in respect of speed gained against fuel consumption.

My suggestion would be to try various settings re RPM/IAS/LPH.

Don't forget that Jodels do cruise nose down in level flight.

[Flyingmac]

I have a 117 with a C90 engine. Performance can vary according to the prop fitted.

I've jumped through all the required hoops to get approval for a Hoffman prop.

Properly trimmed, it's giving me 100kts @2200 RPM. ROC is down by around 50 fpm but take-off roll seems unaffected. (Less than 200mtrs).

Fuel burn is around 15-17ltrs per hour.

Croqueteer. The slightly rough running at 2300 RPM could be due to a slightly rich mixture. Try leaning it off. If it smooths out then it probably needs the carb adjusting.

[ChampChump]

I had three years with a D120 (no airbrakes). Cruise was happily in a range from 75-100 with rpm appropriate for the C90 and a fuel burn of 15-18lph. I tended to cruise on the slow side, to enable loose formation work. They do what they do, most efficiently. I can't remember the ROC, but better than 500 fpm and the short field capability was impressive, especially during wet winter conditions.

Given the small queue waiting to buy her, I think I had a good 'un, on the lightweight side. The current owner might be able to help with figures if you want me to put you in touch.