Menu Sign In Contact FAQ
Banner
Welcome to our forums

DR 400 Regent

My Aircraft was fitted with a compromise prop by the last owner and while I was based at a smallish private strip I was not inclined to change a prop that gave me the ability to lift the payload safely off the ground while returning reasonable cruise performance.

Having moved to an airfield with longer runways take off performance is now much less critical so the cruise prop that is the normal fit for the Regent is very much on the agenda. I have managed to get a copy of the MT E-435 flight manual amendment and this shows nothing to be gained in the cruise performance as like most of the offerings for the DR400-180 it is aimed at making a glider tug a passable touring Aircraft.

Of course it all depends on the wear and tear of your prop, but Sensenich can be overhauled / zerotimed for a fraction of price of a new one. It’s a simple procedure. I know some people who have chosen cut the costs even further by polishing, re-painting and rebalancing their props. They are certainly missing the very nice “Sensenich” stickers and form one, but performance wise there is little difference.

The spar issue is simply one of serial numbers, the early Aircraft did not have a problem as do the later ones and the SB clearly sets this out.

The propellor issue is clearly one that favours the fixed pitch prop if you are looking for cruise performance, the MT retrofit props are aimed at the German glider tug requirement to increase the takeoff and climb performance at the expense of cruse performance, the different exhaust system required with these props may also have an effect as these are attractors of drag.

As most of these CS props had been approved a long time back I think there is reason to re-visit the subject with the latest blade technology but it is doubtfull if this will stack up economicly, I guess it may be time to start looking at the £/$ rate to find the most favourable time to buy a new Sensenich.

I concur that 500m at MAUW is perfectly doable in experienced hands with a 2 blade Sensenich on a 180hp Lycoming.

We often achieved that and would then go on to cruise at 2500ft, 2500rpm (our tach green arc was 2400 to 2700) burning around 38lts/hr 120kts ias.
At 105 kts (flying with 172’s or cherokee’s)
Fuel burn was hugely reduced.

United Kingdom

My aircraft is equipped with a fixed pitch Sensenich prop and I can easily take off from 500 m grass strips at MTOW (1100kg), zero wind and temp ca +22-25 C. VP prop would improve take off performance, not question about that but I hardly need it. In cruise, there is no noticeable performance difference between FP Sensenich and VP Hartzel. Hartzell has slightly shorter blades which probably make it less efficient.
Last but not least: from inception Jodels were engineered with fixed pitch props and fixed gear. O360 can give you only so much power and so much performance. If you want more speed, then get yourself a Bonanza
@Regent, the last piece of advice I can give you is that buying a second hand wooden airplane is like buying a piece of art. You need to be patient and careful because there are lots of neglected airframes with fresh paint sprayed on top of them, cleaned upholstery and polished glare shield. A well cared for wooden structure should look like new:

Thats true, MT does not know about the MTV-18 which is also an option. You will find this one mentioned in the LBA type certificate where it is in the approved propeller listing.

@Robin_253, and all the others, thanks für completing my picture. For sure i would prefer to get a plane without the spar issue, but this is a question of availability…So again, if anyone knows where to find one i would be happy to hear

Thanks for looking, the aim with the prop change is efficiency in the cruise with good take off & climb performance.

I don’t see the aircraft getting a better top speed but the target is to be able to cruise at a lower RPM and save some fuel.

There area number of props approved under German modifications that have grandfather rights under EASA and I’m getting the feeling that MT have forgotten what they have had approved in the past.

Thanks for posting the picture. @Regent has the full picture now.
I’m not gonna debate you, there is no point.
As your question about the E-435 is concerned, I did have a good look here and there but unfortunately I didn’t find the flight manual supplement.
In general I would say that IMHO a two blade propeller would be the best solution for O360 in terms of efficiency and weight.

I fail to see what other elliments are to be addressed , the problem with the Aircraft was the bonding of the spar structure in that the glue might not meet the strength required. To prove this the wing structure would have to be dismantled ( likely to involve destruction of the structure.

The fix was to glue extra structure into the spar web to garentee that there would be sufficient glued area to meet the design strength.

The solution is not in engineering terms very eligent but it does the job.

The new structure can be seen in the spar web.

A_and_C wrote:

I am having trouble with translation of the above report

This might help

A_and_C wrote:

aircraft that had a structural failure was performing aerobics,

This hypothesis has been officially ruled out. Kindly have a look at the accident report I’m referring to.

A_and_C wrote:

Robin did step outside this best practice

That’s an euphemism, to say the least

A_and_C wrote:

for a while

+20 years to be a little bit more precise

A_and_C wrote:

the spar modification addressed any issues

Well, I certainly wouldn’t say so. The aim of the AD is to prevent the affected airframes from falling from the sky. Period. Wing spar is inspected and repaired but all other elements are not.

33 Posts
Sign in to add your message

Back to Top