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Shupe Howard 500 fuel/range issues


roop298

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Flying the Shupe (et al) Hughes 500 super ventura

Ok, I'm a bit of a novice and my maths isn't the best.  I'm having problems getting flight range right for this aircraft.

This plane has a range of 2200nm (cruise altitude not specified) at, presumably cruise power.

I've just flown a flight of 500nm with 2145kg of fuel.  According to my calcs that should have given a range of circa 800nm.   Now I know this is dependent on power settings and altitude but I only got <500nm with a 340@23 wind at 15000ft while flying predominantly due east.

Power setting 40 at 2200 (mixture to match best BMEP) approx.  I didnt write it down.

I've also noticed the fuel tank selection is a bit odd for this plane but I think I've got my head around that now.

I'd like to know the best power settings/altitude but I cant find any data, too.

 

HAve I got it all wrong?

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The Howard 500, as you know, was a ‘souped-up’ Ventura and as such was fitted with more powerful supercharged engines. Are the superchargers modelled in Milton Shupe’s Ventura and, if they are, did you switch to high blower during the climb (usually above about 12,000ft)?

I am not familiar with the power settings on the Howard 500, but 40” seems a little high if you are looking for an economic cruise setting to achieve maximum range in a piston engined aircraft. The cruise altitude is also an important consideration in terms of getting maximum range and generally the higher the better. So it might be worth experimenting a bit and perhaps try lower power settings (30-33”) with mixture leaned at a higher cruising altitudes to see if that stretches out the range a bit more.

Bill

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Thanks for the reply.

There is one doc referencing high and low blow but I don't see anything in the checksheets for 'cruise'.  I'll try what you suggest but at 30inches I don't thing I'm going to get anywhere near the published cruise speed.  It also states a service ceiling around 25000 but I'm not sure this thing'll even run.

TBA

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In any case FSX/P3d does not correctly model superchargers (if at all).  Doug Dawson made a module which gives this functionality, and it is used to good effect in Manfred Jahn's Constellation and presumably in other propliner models.  I downloaded the Howard file and there is no sign of the module in the panel.cfg.  There's also a picture in the panel documentation that says "supercharger levers - inop for now" so I guess it hasn't been implemented.

Certainly the lack of superchargers will affect the model if you try and fly by the numbers.

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Ok.  I'll search for the module.

As it turns out I still couldn't get anywhere near 'the numbers'.  I fueled for a 1251nm trip and ran out after 951nm.  That's flying at 24000 and 33"/2250 with ff's of around 109 (gal/hour??).  As I lost weight speed went up from 279 to 303kmh.  Throttles were at 87%. Winds aloft were 52@48 and I was flying due south.

As I NEVER fly this envelope strictly speaking this is a non-issue however, as my hands on experience increases, it vexes me that I can't run a simulated flight.

As the Shupe stuff is known for it's attention to detail I suspect the fault is with me and my calculations.

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And another thing.  Once Ive' set map and rpm I lean off to maximise BMEP.  What kind of fuel saving would I get if I leaned off a bit more (with a small drop in BMEP)?  Would you even do that?  I know about lean of rich in small stuff but would you do it in anything bigger?

No go on the DD blower module.  Links are broken.  I think what I'm going to do is brim it then fly it until it runs out of juice.

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The module itself won't help you if it isn't referenced in the panel.cfg (which it isn't).

There's some good stuff on flying propliners at Propliner Tutorial (calclassic.com)   Nothing specific to the Howard, but plenty on the DC-6 and Connie.

(Actually the whole site is worth a look, it has some great planes, including the Constellation I mentioned above)

.

 

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I hadn't flown the Howard for many years (since my FS9 days in fact) but I got the FSX version out of my hangar and took it up this afternoon - it really is a very nice piece of freeware with a great external model and great sounds! At 19,000ft having taken off at maximum weight with full tanks I was getting 157kts indicated (equates to around 210kts true airspeed) with power settings of 33/2200 and the mixture considerably leaned (until the BMEP started to drop off). At those settings the fuel flow per engine was 107GPH which basically means that it would have a range of little more than about 1500nm with full tanks. This is quite a bit below the book figure of 2200nm although I guess that is calculated on the basis of using the superchargers if these were functional and perhaps a higher cruising altitude but, as you know, the blower controls in this model are non-functional. 

Bill

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2 hours ago, scianoir said:

I hadn't flown the Howard for many years (since my FS9 days in fact) but I got the FSX version out of my hangar and took it up this afternoon - it really is a very nice piece of freeware with a great external model and great sounds! At 19,000ft having taken off at maximum weight with full tanks I was getting 157kts indicated (equates to around 210kts true airspeed) with power settings of 33/2200 and the mixture considerably leaned (until the BMEP started to drop off). At those settings the fuel flow per engine was 107GPH which basically means that it would have a range of little more than about 1500nm with full tanks. This is quite a bit below the book figure of 2200nm although I guess that is calculated on the basis of using the superchargers if these were functional and perhaps a higher cruising altitude but, as you know, the blower controls in this model are non-functional. 

Bill

Well you've ended up where I'll probably be after a few flights!  On the range front; I don't mind that it's not book value.  I'd just rather know what the actual is so I can plan.

I emailed Milton Shupe this afternoon.  I wasn't aware he'd pulled back from this stuff but he said that there are a number of models and ports out there all with differing perf specs.  He suggested a cfg tweek.  I declined and said I'd go to flight testing.  So here it is so far:

BTW will look on the props site.  I'm a big twin prop fan.

 

 
322ltr fuel (85GAL)
 
 
 
         
             
  height MAP RPM KpH Range  
  1000 50 2400 516 53  
  1000 40 2500 445 66  
  1000 40 2500 453 68  
  1000 32 2400 332 76 ***
  CANNOT MAINTAIN SPEED AT 30"          
             
             
  5000 50 2250 526 64  
  5000 40 2325 431 75  
  5000 30 2200 318 93 ***
  5000 29 2100 296 95

 

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40 minutes ago, roop298 said:

Well you've ended up where I'll probably be after a few flights!  On the range front; I don't mind that it's not book value.  I'd just rather know what the actual is so I can plan.

Well I’ll probably never need to make use of its maximum range as I generally get bored if flights are more than an hour or two so I tend to fly relatively short segments as a rule! I’m a great fan of classic big props too but on transatlantic flights I prefer to make a series of hops using Iceland and Greenland as stopping points apart from when I’m using the great A2A Connie which I have tended to fly direct, using the nice little Ocean Stations freeware to aid navigation.

Bill

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