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Considering the Jumo replaced the BMW 801 in the Fw 190, does that make the DB third best?Mainly curious. I've seen here some references to certain Luftwaffe aircraft having to "settle" for the Jumo engines when DB engines were all spoken for. I know there were production limitations, but what other factors made the Jumo engines "second best"?
Mainly curious. I've seen here some references to certain Luftwaffe aircraft having to "settle" for the Jumo engines when DB engines were all spoken for. I know there were production limitations, but what other factors made the Jumo engines "second best"?
Jumo vs DB:
standard supercharger with different speeds vs variable coupling
3 valves per cylinder vs 4
There is a lot more to it, but in all seriousness if you`re interested in stuff like this you really do need my book!
i'm trying to decide if i'm intelligent enough to understand it before i buy mine !I am waiting for Father Christmas to bring my copy.
Hmmm well I did spend 6 years putting it all in a book to clear up these points.... was rather hoping someone might have read it by now !
1) The Jumos until the 213 dont have an actual "kommandogerat" (my definition of that is ONE single "box" which does everything in ONE unit), prior to the 213
they`re like the DB, in that they have a couple of distributed systems which broadly achieve the same thing as the "kommandogerat", but its not
all stuck into one unit. So the 211 for example has separate boost control and fuel control boxes. They can be described as "single-lever" for the most part,
but this is not achieved by a single-master control box (the kommandogerat).
2) The DB doesnt have a "variable length inlet manifold".
3) The lack of head bolts on the DB does not permit greater swept volume, the limit to engine length and bore size/spacing is always the minimum
gap needed between the cylinders where they meet in the middle, not where the bolts are. The 211 is actually larger in capacity than the 601,
and nearly as large as the 605. I think you`ve got mixed up comparing the very early 210 with the 601.
4) The Jumo does have lower CR, and indeed the DB had higher CR to improve fuel economy and altitude performance, but,
due to other factors this still left the DB with at best equal and usually slightly worse fuel economy than the Jumo.
other points about pressure cooling and valves are correct, except for the assertion that it doesnt matter how many you have because
"american engines only had 2 and were ok". Indeed, and they would have been "even more ok" with 3 or 4.... however its a huge pain
with the valvegear on a radial to have more than 2, so most dont.
Broadly:
601A < Jumo211A (due to very poor "box" type supercharger of the jumo)
601E = Jumo211J (pretty comparable, 211J has much better supercharger)
605A > Jumo211J (605 has slight advantage in swept volume)
605A < Jumo213A (213 is a much later developed, more modern engine, so is naturally a bit better overall)
All Jumo`s had outstandingly good oil systems, which helped them avoid the worst of the bearing troubles which DB experienced.
There is a lot more to it, but in all seriousness if you`re interested in stuff like this you really do need my book!
Well there is this article in enginehistory.org
Daimler-Benz
Which shows that from the DB601E onwards a radical valve overlap was introduced that lead to low speed problems.
The solution was a secondary induction system, which activated at low rpm and which looks longer path to me.
This is what I received from Amazon. I missed it due to spam and only checked now. Preorders have never worked for me.
"Hello,
We're contacting you about order #250-2788350-5525440 for the following item(s):
Secret Horsepower Race, The: Western Fighter Engine Development
We're unable to fulfill your order for the item(s) listed above because they are no longer available from the supplier. As a result, we've had to cancel them from your order and your original payment method won't be charged for them.
We're sorry for any inconvenience or disappointment this may have caused."
i'm trying to decide if i'm intelligent enough to understand it before i buy mine !
I got the same thing from Books A Million.
Well there is this article in enginehistory.org
Daimler-Benz
Which shows that from the DB601E onwards a radical valve overlap was introduced that lead to low speed problems.
"
ah !I had a sneak peek before it was stashed away and there were lots of pictures to look at
Well there is this article in enginehistory.org
This is what I received from Amazon. I missed it due to spam and only checked now. Preorders have never worked for me.
"Hello,
We're contacting you about order #250-2788350-5525440 for the following item(s):
Secret Horsepower Race, The: Western Fighter Engine Development
We're unable to fulfill your order for the item(s) listed above because they are no longer available from the supplier. As a result, we've had to cancel them from your order and your original payment method won't be charged for them.
We're sorry for any inconvenience or disappointment this may have caused."