We've all seen these posts over and over. Posts stating that something is over or under modeled as a plain fact with nothing to back it up. These posts are completely and absolutely useless and can even be harmful when new players are gathering information and see those claims so confidently stated. HTC is not perfect, nor do they claim to be perfect, and they have modified unit performance repeatedly through this game's history based on supplied evidence.
Here is how
not to do it:
so you can take your pompus attitude and shove it 
theres alot of things the brewster does in game it shouldnt do, and the charts say it cant do, so like i said, going by JUST the chart its not only naive, but insanely blind.
But next time i got a spit16 barreling down on me, i'll make sure to PM him and tell him his spit isent capable of doing that. because the "charts" say so 
The poster starts with a confrontational attitude. He then follows up by making hard claims that a unit in the game does stuff the real one could not do and goes on to insult that those who use charts as evidence. He then conflates test data with a combat situation as anecdotal evidence.
If HTC even reads this, they are not going to think "Hmm, maybe there is something we missed in our modeling of that unit. Lets look at it again."
Another "how not to do it":
It seems to me that either the Mosquito is not carrying a full fuel load or its fuel burn rate is much higher than other aircraft in AH. The Mosquito FB.VI had a range of 1,800 miles on internal fuel. It seems to barely fly further than the Spitfire MkIX in AH. Last night I took a Mosquito with full fuel and droptanks and only managed 8 sectors or so before landing on fumes.
The Mosquito FB.VI had a range of 1,800 miles.
The Spitfire MkIX had a range of about 600 miles.
The Mosquito carries 539 Imp gal of fuel internally, or 269.5 Imp gal per engine. It has two 68 Imp gal center tanks, two starboard inboard tanks with the inner tank holding 78 Imp gal and the outer tank holding 65.5 Imp gal, two starboard outer tanks with the inner tank holding 34 Imp gal and the outer tank holding 24 Imp gal, two port inboard tanks with the inner tank holding 78 Imp gal and the outer tank holding 65.5 Imp gal and two port outer tanks with the inner tank holding 34 Imp gal and the outer tank holding 24 Imp gal. This is about 3,400lbs of fuel. (This info is specific to the Mosquito B.XVI, but I think it is generally accurate for all Mosquitoes)
The Spitfire MkIX carries 85 Imp gal of fuel internally, a 48 Imp gal upper tanks and a 37 Imperial gallon lower tank. This is about 530lbs of fuel.
There are lots of numbers in this post and the information is presented in a non-confrontational manner, but there are also no sources used to support the claim. Due to the lack of sources it is not a useful post and did not result in any change to the claimed error.
This post resulted in the requested change being implemented in the following version of AH:
Some time ago I stated that I felt the Mosquito consumed fuel too rapidly. As evidence I gave the fact that the Spitfire Mk IX has greater endurance than does the Mosquito in AH.
Spit_9 -- 35/+21=56
Mossie -- 34/+16=50
The original thread can be read here: The Mossie's flight endurance still seems too short
Acting on advice from that thread I obtained a PDF file of the Pilot's Notes for the Mosquito FB 6 from snafu's website. The Pilot's Notes for the Mosquito FB 6 can be found by clicking on the Pilot's Notes link on snafu's website.
On page 11 of the pilot's notes it lists the fuel capacity of the Mosquito FB 6's various fuel tanks:
MAIN SUPPLY
Centre tanks....................50 gallons
Inner tanks....................286 gallons
OUTER TANKS................116 gallons
_____________________________
Total........................ .....452 gallons
Long-range tank...............63 gallons
Wing drop tanks..............200 gallons
(2 x 100 gallons)
_____________________________
Total fuel capacity...........715 gallons
(Interestingly this is less than the total internal fuel capacity of 543 gallons listed on the HiTech Creations Mosquito page)
On pages 30-33 of the pilot's notes there are flight planning charts that give the fuel consumption for various speeds, weights and altitudes.
For the ease of calculations I selected settings that would consume fuel at a rate of 100 gallons per hour so that I could simply use the 50 gallon Centre tank. If the fuel consumption was correct, then the fuel should last half an hour.
The settings were:
AUW: 17,000lbs
Altitude: 10,000ft
RPM: 2,400
TAS-KNOTS: 275
TEST SETUP
Using the AKDesert map in offline mode I set the fuel consumption to 1.0000. I selected A56 as my take off field, planning a southwest flight along the channel.
To get roughly an All Up Weight of 17,000lbs I set the Mosquito to full fuel, no external or internal stores, 150 rounds per 20mm gun and 500 rounds per .303 gun.
TEST
Once on the runway I selected the right inner (RI) fuel tank before starting the engines so as to keep the centre tank (AUX) full.
I then took off, climbed to 10,000ft and set a southwest heading.
I then reduced my RPM settings from 3,000 to 2,400 and reduced my boost setting from 14lbs./sq.in. to 8lb./sq.in.
The Mosquito's airspeed declined until it settled at about 265mph. (This was 265mph true airspeed, not indicated airspeed)
I then switched to the AUX tank and started a timer simultaneously.
RESULTS
The AUX tank was drained in 13 minutes and 52 seconds which indicates a fuel consuption rate with those settings of approximately 200-225 gallons per hour, or more than twice the fuel consumption listed for those settings in the Flight Planner Charts of the Pilot's Notes for the Mosquito FB 6.
CONCLUSION
The Mosquito FB.Mk VI in AH is consuming fuel at more than twice the rate it should be. If the AUX tank also includes the 63 gallon Long range tank (which given AH's higher listed fuel capacity it may be) the fuel consumption would be more than four times the rate it should be.
This post referenced a primary source document and explicitly spelled out the test figures and methodology. It was probably more detailed than required, but it gave solid evidence that could be tested, verified and acted upon by HTC if they decided it was important enough.
SUMMARYIf you really think something is over or under modeled, don't state it as fact on the forums. Research it, find supporting evidence, primary source if at all possible, and post detailed results of your testing and data collecting efforts. Doing otherwise is wasting time and will result in no change. It is possible that in doing research you will find information that shows HTC has it modeled correctly as well. When you post statements about over or under modeling based on your feelings and/or vague understandings you do both yourself and others a disservice.
