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Author Topic: Viscount 810 revisited  (Read 831 times)

Offline travelair

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Viscount 810 revisited
« on: March 05, 2014, 08:58:28 PM »
After reading this old thread https://www.airwaysim.com/forum/index.php?topic=34698.0, calculating the in-game numbers and doing research on the net, there are reasons to believe the numbers used for the V810 are off, unfortunately quite a bit too, crippling the plane.
The motivation behind this not solely that I operate a Viscount fleet in this game (I ordered Electras to expand) but more the fact that the V810, according to all sources I came apon, was a plane alot more capable than what it is able to in AWS. So maybe there is a chance its performance could be reevaluated.

First off, all sources (I wont list them all yet) refer to the V810 as an improved range variant of the V800, attributed to the use of the RR Dart Mk 525 on that type. Yet the description used in the game (if you do not check the payload vs. range chart right away) is quite confusing, giving the impression the V810 actually has less range that the V800 when in fact it doenst. To illustrate that point, here are the numbers: (obviously the weight/ range ration calc. used produces these strange results, not sure where the game got its numbers, but more on this later)

V800 - 74 pax/ Range 420nm - 65 P/ R: 600nm - 59 P/ R: 720nm - 55 P/ R: 800nm   - 49 P/ R: 920nm
V810 - 74 pax/ Range 310nm - 65 P/ R: 700nm - 59 P/ R: 950nm - 55 P/ R: 1030nm - 49 P/ R: 1080nm

Here is a look at the 700D:
59 P/ R: 900nm - 55 P/ R: 1030nm - 49 P/ R: 1160nm

Its nearly impossible to get acurate pax to range ratio figures on any webpage, but one thing should be obvious: Its highly unlikely that Vickers would have been able to sell a single improved range V810, if the ratio would have been the way the game calculates it (equal at 55 P or even worse at 49 P), besides the plane was specifically designed to hold an increased amount of pax, at least at equal the range the V700D had offered.

The weights:
V70D - MTOW: 29256 - Max.Payload: 6345 - OWE: 22911
V800 - MTOW: 29256 - Max.Payload: 7629 - OWE: 21627   (keep in mind, the V800 was a 1,2m stretch over the 700, yet here it weighs 1,28t less than the former)
V810 - MTOW: 31297 - Max.Payload: 7050 - OWE: 24247   (the only difference between 800/810 are the upgraded engines used, RR 525 vs. 510/520, yet it weighs 2,6t more)

Taking these numbers into account, the V800 would have the largest range of all, yet it doesnt. Also the fact that the V810s range is 80nm less at 49 P than V70D and the sharp drop between 59 and 65 P of 250nm are very questionable. Calculating 1 pax & luggage at 100kg, the V810 would have at least the same range as the V70D at 65 vs. 59 seats, meaning 200nm more than now, which would also increase its range at 74 P noticably.

A very interesting read is this excerpt of a book written by Heino Caesar http://books.google.de/books?id=tL4MK5DnffIC&pg=PA323&lpg=PA323&dq=viscount+810+reichweite&source=bl&ots=OCIPaWTqVq&sig=MCrCWAyhHmWpYuH5xJ9apVfslco&hl=de&sa=X&ei=o4cXU5j4AcOJtQbxv4Eo&ved=0CFQQ6AEwBQ#v=onepage&q=viscount%20810%20reichweite&f=false. He was a V810 copilot for Lufthansa, which operated 11 Viscounts with 64 seats from 1958 on. The book is in german, I will translates what he writes:
"The V810, at max payload (64pax) had a range of about 1900km or about 1025nm"
There is no reason to believe that he has any motivation to write down false numbers...

Another interesting read is http://www.vickersviscount.net/, especially the history category...
I will contact them to try to get a definite answer to the range question regarding the V810

Taking into account the weights used by the game, what the LH copilot said about the plane and the many sources available incl. data from British Civil Aircraft since 1919 used by Wiki plus the fact, that not a single document points towards the V800/810 as being a short range plane (300-400nm), I suggest the range of the V810 should be adjusted to at least 900nm at 64 pax and figured up and down from there. The plane deserves a more realistic assessment of its capabilities.

I will keep investigating this case!
cheers and thanks for reading  :D


« Last Edit: March 05, 2014, 09:13:44 PM by travelair »

Offline chiveicrook

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Re: Viscount 810 revisited
« Reply #1 on: March 05, 2014, 10:28:57 PM »
The biggest problem with Viscount is that it's impossible to add all possible variations to the game - here a quote from Flight magazine from 1955:
Quote
Superficially, there appear to be few differences between any aircraft in the V.700 series; in fact, each Viscount customer has influenced the design and construction of his particular aircraft, although to a varying extent. It might thus be said that there is no such aircraft as standard Viscount

Variants for NA market had apparently vastly different characteristics and also operated under different regulations. Different types had different recommended cruising speeds, which also can't be implemented in game.

Now, if you could find a manufacturer recommended flight manual with all kinds of data for all/most variants I'm pretty sure Sami would happily accept all fixes.

Offline travelair

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Re: Viscount 810 revisited
« Reply #2 on: March 06, 2014, 08:37:32 PM »
The way the game handles the 4 Viscount types produced is fine, there is no way to put in regulatory differences or recommended cruising speeds, although there was only a very slight difference between certain operators.
Is there a link to the article? The quote is most likely refering to seat count, lounges on board, extra slipper fuel tanks which were available, not much else was variable according to www.vickersviscount.net/

Here is an interesting read, also from 1955: http://www.flightglobal.com/pdfarchive/view/1955/1955%20-%201509.html

To summarize, T.A.A. operated V700`s with 44 seats, extra tanks which increased fuel cap. by 290 gal. to a total of 2240 gal. and a conservative range of 1550nm (400 gal. reserve)
If you put the range/ fuel factor on a regular 700 gives results in a range of at least 1350nm. (The tanks + fuel have a weight too)

In-game a V70D with 45 pax has a range of 1230nm. Its close but these 120nm would make a huge difference relative to increased pax load.

Another example: Central African Airways had a number of 700s, configured at 47 pax and slipper tanks. Have a look at their timetable, CE893 flew from Rome to Khartoum non-stop, which is a distance of 1891nm. I guess they were comfortable with less reserve on the flight.
http://www.vickersviscount.net/Pages_History/CAA%20timetable.aspx

I wont be possible to get a flight manual covering all variants, but these documents + the LH pilot account proove, that the range numbers in-game are too low, especially for the V810. Please look at the weights again: With the increased payload, the V810 should have a least the range of the V70D at 65 vs 59 P. yet its range drops by 250 nm! and at 49 P. its range is less than that of a V70D. How obvious can it get?

I dont think the LH pilot is making up the numbers he used in the book, why should he? According to him, the plane was able to fly around 1025nm at 64 pax. If the V810 would have a range of 950nm at 65 pax, it would bring it more in line with what we see here and it would not turn the Viscount into a "super" plane.



« Last Edit: March 06, 2014, 08:39:52 PM by travelair »

Offline chiveicrook

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Re: Viscount 810 revisited
« Reply #3 on: March 06, 2014, 09:17:44 PM »
http://www.flightglobal.com/pdfarchive/view/1955/1955%20-%200971.html
Quite lengthy article.

It seems that changes were sometimes quite extensive, for example in one place it says that Capital Airlines ordered an expansion of fuel tanks from 1720 imp. gal. to 1916 imp. gal and also requested a provision for attachment of external fuel tanks containing 290 imp. gal.

Collect sources, write a summary and proposed changes and present it all to Sami :-)

Offline chiveicrook

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Re: Viscount 810 revisited
« Reply #4 on: March 09, 2014, 06:00:29 PM »
How does new engine variant of 810 look to you ? ;)

Offline travelair

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Re: Viscount 810 revisited
« Reply #5 on: March 10, 2014, 05:15:15 AM »
It looks great... It reduces fuel consumption by roughly 4%! No change in range. I think we all agree, thats what Vickers did during that time, stick some new RR engines over the wings to save some fuel, thats what airlines wanted during the 50s, you know, when fuel was unbelievably expensive...  :'( They were still not able to reach half of europe or the US (with an increased weight and range variant), eventhough there is quite some proove, they could with the 810, but does one really care...lets just buy the Conny or DC6/7, or any other prefered type besides the Visc. I wont even start investigating the range of these planes, it gets tiresome and I do have other things to do as well  :laugh:
 
Range calculation is not the only "mechanic" used in game which is a bit questionable - turn around times for planes carrying 100pax more, although it is the same type, should really be on high priority to be fixed. For now we got the new financial overview, every accountans wet dream...
 
But I was lectured before, that the game cant handle variable turn around times relative to pax on board, too bad  ::)
« Last Edit: March 10, 2014, 06:42:57 AM by travelair »

Offline chiveicrook

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Re: Viscount 810 revisited
« Reply #6 on: March 10, 2014, 06:49:09 AM »
Well, actually the range is a bit different according to payload graphs. It seems to hang on to more pax longer with new engine. I'm not sure if it's visible from new route creation though.

Offline travelair

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Offline travelair

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Re: Viscount 810 revisited
« Reply #8 on: March 10, 2014, 12:09:48 PM »
Viscount 840  :o It was proposed by Vickers, but not a single one was built with Darts 541, only 6 for CAAC - they used the older 525 engines. I didnt expect it to show up in-game...
http://en.wikipedia.org/wiki/Vickers_Viscount_variants

But all aside,  I finally found a document, after reading everything I could about Visc for days now, which prooves that the ranges in game are way off. It is from a very respectible source, I dont think Sami can deny that. The numbers are probably from Vickers itself, I could try to contact flightglobal to find that out...
www.flightglobal.com/pdfarchive/view/1958/1958-1-%20-%200124.html

To summarize, all ranges are at max. payload:

V70D - 1340mi - 2150km - 1164nm - Game: 900nm - Cr.Speed: 282 kts (game uses 280 kts)
V800 - 790 mi - 1271 km - 686nm - Game: 420nm - Cr.Speed: 275 kts
V810 - 985 mi - 1585km - 856 nm - Game: 310nm - Cr.Speed: 317 kts
V840 - 1070 mi - 1720km - 930nm - Game: 660nm - Cr.Speed: 348 kts

Speeds for the 810/840 are also not correct, but lets forget about that for now. The range issue is much more important. These numbers are in line with what I read across the board, also they show that the 800/810 were never only able to fly 420/310 nm. If Sami would share the source where he gets these numbers, but Im pretty sure he wont. This leaves them in the realm of fantasy.

One more thing on the speed of the 810 (from http://www.vickersviscount.net/Pages_History/The_Turboprop_World-Beater_VISCOUNT.aspx):

"Deliveries to Continental began shortly after FAA type certification for the V.810 in April 1958. The new variant could handle a gross weight of 67,000lbs (30,454kgs) at take-off, with a payload of 15,000lbs (6,818kgs), and maintain a cruise speed of 365mph (588kph, 317 kts). Continentalís order was followed by nine other national airlines and many independents, and final production totalled 84."

Ok, I have done my homework, I dont know what else Sami needs to be convinced that the Viscount deserves to be re-evaluated, and it would be nice for him to spare a comment on this issue.
« Last Edit: March 10, 2014, 12:24:32 PM by travelair »

Offline chiveicrook

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Re: Viscount 810 revisited
« Reply #9 on: March 10, 2014, 12:40:32 PM »
Oopsie, I must have looked at wrong graphs ^^


Post your findings from last post in bug report forum, let's see what Sami thinks. Even if he frequents ordinary sub-forums the proper way is to post it in bug report section ;) I think that for range adjustment it will be enough. Unfortunately, speed has to be identical across the fleet-type and adjustments usually require much more detailed data.

 

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