Just tried it. The switch has no effect, neither in 39 nor modernized. I can move the throttles about the same and it results in the same low MP. So below 1 ata (1 standard atmosphere, so it does not get up to full power if you do not start close to sea level elevation) or below 29" in the modernized version.
I really would love to use this in onAir but currently that is a no go, as I am in an area that has airports in the 4k ft range and somehow the MP just gets up to a weirdly low pressure. Eventhough outside pressure is well close to 30"
So iâve tried it. And here is my conclusion. It feels indeed alot more floaty then the retrofit version. Take off seems shorter and definately harder to lose speed. Though itâs still quite easy. This run was with default settings starting on the runway (so empty, 50% fuel i believe?) Note that i didnât use full power, since i doubt you would in real life with an almost empty plane and three powerfull engines.
First notch of flaps set before turning base at around 160 kph. second when on final at around 140 kph (you can hear the wind noise) and full flaps at close final around 130 kph. Till this moment i still used some throttle to maintain desired airspeed. Only on close final after setting full flaps i had to close the throttle a few times (you can hear the clicking noises).
Also note that reducing power to 1600 rpm made the plane slow down to 200kph in no time, while below 200 more power reduction was neccesary, and slowing down was a bit harder.
Touchdown and stopping was quite a challenge indeed. Tough i feel that touching down @ 100 kph was a bit to fast in this occasion. It took along time before the tail went down. But once the tail did came down, braking was not a problem. (you wouldnât use full brakes anyway)
So yeah⊠it flyâs differently then the retrofit. But it does slow down well enough imo.
ps. weather was set to âfew cloudsâ preset
Airport was EHAL
Iâve been trying these steps in the 39 version, and I might as well be blowing raspberries for all the effect it seems to have. Even when lined up on the selected heading and stabilized activating the âwhite crossâ button does nothing at all. Is there some other step I might be missing in between? Is there a switch somewhere that needs to be thrown to send power to the LZs4?
All this discussion of manifold pressure not reaching 1 atmosphere, leads my to ask if anyone has compared MP to actual station pressure? Is manifold pressure being compared to altimeter setting?
If altimeter setting is at 30.00" then actual atmospheric pressure is going to be pretty close to 25" at 5000â.
What does the MP read before starting the engine? It should be reading the ambient pressure. After startup it should drop about 1". Example: if the station pressure is 30", then the MP should read 30" before startup. Once running at idle, MP should read about 29", a radial engine should drop slightly more due to the additional plumbing. At take-off power you should expect a further drop to between 24-25".
I have not run a test on the Ju 52, as mentioned earlier, I have not purchased ANY adds yet. Maybe someone should do a quick test to see how well this is modelled. It would also be a fair indicator of whether or not there is a supercharger. If it is indeed supercharged, the drop in MP would be less. How much less would depend on the amount of boost the supercharger is capable of producing.
I would expect this at full throttle, not at idle? A normally aspirated engine runs at a MAP close to ambient pressure at full throttle (as you said, one inch less maybe due friction caused by plumbing). Throttle valve closed, it is supposed to indicate low MAP.
I have seen a video of 1939 version Ju-52 and it doesnât seem to have a manifold pressure gauge in inHg, its in atm.
Iâm not too sure on this one. The BMW engines were (I think) around 770hp each whereas the Wasps are 600. Certainly the Spanish Beta engines which were re-worked BMWs built under licence were 775hp. Iâm not sure how much of the lack of power the C/S props would make up for.
I am in cruise at FL190 in the 1939 version on my way to Lukla. So far this one is smooth as butter. Perfect trim, hands off. No issues with lack of power. I think I am gonna stop flying the Retrofit. Something is goofy there. The 1939 version flies so much better in my eyes. Itâs a joy!
100% with you , started with the 1939 and didnât understand what people were complaining about in the forums. When I finally tried the retrofit , I realized it was a different beast
In fairness though the Ju-52 has 35% higher wing loading than the Do-27, the -27 also has ailerons which droop and full-span leading edge slots which help.
From memory, whatâs left of it, the DC-3 I used to fly, with 1820 Cyclones, would fit right in that description. MP 1" drop at start and about 4-5" drop at 90%. The 1820 pulled air faster than the intake could supply it. Part of the âslurpingâ sound of the engine. The 1340 had bigger pipes so maybe it wouldnât drop so much. Donât know, never flew the 1340s.
I ferried a semi-rebuilt TBF Avenger from Las Angeles to Vancouver for a dusting operation a few years back FYI(If anyone ever asks you to ferry a warbird more than 50 miles, say no.).
That was a R2600 Cyclone. seem to remember a significant drop there too, without the charger.
